diff --git a/java/com/google/gerrit/server/notedb/CommitRewriter.java b/java/com/google/gerrit/server/notedb/CommitRewriter.java
index 7f13731..3cbe546 100644
--- a/java/com/google/gerrit/server/notedb/CommitRewriter.java
+++ b/java/com/google/gerrit/server/notedb/CommitRewriter.java
@@ -20,6 +20,7 @@
 import static com.google.gerrit.server.notedb.ChangeNoteUtil.FOOTER_LABEL;
 import static com.google.gerrit.server.notedb.ChangeNoteUtil.FOOTER_REAL_USER;
 import static com.google.gerrit.server.notedb.ChangeNoteUtil.FOOTER_SUBMITTED_WITH;
+import static com.google.gerrit.server.notedb.ChangeNoteUtil.FOOTER_TAG;
 import static com.google.gerrit.server.util.AccountTemplateUtil.ACCOUNT_TEMPLATE_PATTERN;
 import static com.google.gerrit.server.util.AccountTemplateUtil.ACCOUNT_TEMPLATE_REGEX;
 
@@ -39,6 +40,7 @@
 import com.google.gerrit.entities.SubmitRecord;
 import com.google.gerrit.git.RefUpdateUtil;
 import com.google.gerrit.json.OutputFormat;
+import com.google.gerrit.server.ChangeMessagesUtil;
 import com.google.gerrit.server.account.AccountCache;
 import com.google.gerrit.server.account.AccountState;
 import com.google.gerrit.server.account.externalids.ExternalId;
@@ -169,7 +171,8 @@
       Pattern.compile("Assignee changed from: (.*) to: (.*)");
 
   private static final Pattern REMOVED_REVIEWER_PATTERN =
-      Pattern.compile("Removed (cc|reviewer) (.*)(\\.| with the following votes)");
+      Pattern.compile(
+          "Removed (cc|reviewer) (.*)(\\.| with the following votes:\n.*)", Pattern.DOTALL);
 
   private static final Pattern REMOVED_VOTE_PATTERN = Pattern.compile("Removed (.*) by (.*)");
 
@@ -185,12 +188,18 @@
 
   private static final Pattern ON_CODE_OWNER_ADD_REVIEWER_PATTERN =
       Pattern.compile("(.*) who was added as reviewer owns the following files");
+
+  private static final String CODE_OWNER_ADD_REVIEWER_TAG =
+      ChangeMessagesUtil.AUTOGENERATED_BY_GERRIT_TAG_PREFIX + "code-owners:addReviewer";
+
   private static final String ON_CODE_OWNER_APPROVAL_REGEX = "code-owner approved by (.*):";
   private static final String ON_CODE_OWNER_OVERRIDE_REGEX =
       "code-owners submit requirement .* overridden by (.*)";
 
   private static final Pattern ON_CODE_OWNER_REVIEW_PATTERN =
       Pattern.compile(ON_CODE_OWNER_APPROVAL_REGEX + "|" + ON_CODE_OWNER_OVERRIDE_REGEX);
+  private static final Pattern ON_CODE_OWNER_POST_REVIEW_PATTERN =
+      Pattern.compile("Patch Set [0-9]+:[\\s\\S]*By (voting|removing)[\\s\\S]*");
 
   private static final Pattern REPLY_BY_REASON_PATTERN =
       Pattern.compile("(.*) replied on the change");
@@ -583,7 +592,7 @@
     }
     Matcher matcher = REMOVED_REVIEWER_PATTERN.matcher(originalChangeMessage);
 
-    if (matcher.find() && !ACCOUNT_TEMPLATE_PATTERN.matcher(matcher.group(2)).matches()) {
+    if (matcher.matches() && !ACCOUNT_TEMPLATE_PATTERN.matcher(matcher.group(2)).matches()) {
       // Since we do not use change messages for reviewer updates on UI, it does not matter what we
       // rewrite it to.
       return Optional.of(originalChangeMessage.substring(0, matcher.end(1)));
@@ -731,7 +740,11 @@
     if (Strings.isNullOrEmpty(originalMessage)) {
       return Optional.empty();
     }
-
+    Matcher onCodeOwnerPostReviewMatcher =
+        ON_CODE_OWNER_POST_REVIEW_PATTERN.matcher(originalMessage);
+    if (!onCodeOwnerPostReviewMatcher.matches()) {
+      return Optional.empty();
+    }
     Matcher onCodeOwnerReviewMatcher = ON_CODE_OWNER_REVIEW_PATTERN.matcher(originalMessage);
     while (onCodeOwnerReviewMatcher.find()) {
       String accountName =
@@ -823,7 +836,9 @@
     for (FooterLine fl : footerLines) {
       String footerKey = fl.getKey();
       String footerValue = fl.getValue();
-      if (footerKey.equalsIgnoreCase(FOOTER_ASSIGNEE.getName())) {
+      if (footerKey.equalsIgnoreCase(FOOTER_TAG.getName())) {
+        fixProgress.tag = footerValue;
+      } else if (footerKey.equalsIgnoreCase(FOOTER_ASSIGNEE.getName())) {
         Account.Id oldAssignee = fixProgress.assigneeId;
         FixIdentResult fixedAssignee = null;
         if (footerValue.equals("")) {
@@ -954,7 +969,8 @@
       fixedChangeMessage =
           fixCodeOwnersOnReviewChangeMessage(fixProgress.updateAuthorId, originalChangeMessage);
     }
-    if (!fixedChangeMessage.isPresent()) {
+    if (!fixedChangeMessage.isPresent()
+        && Objects.equals(fixProgress.tag, CODE_OWNER_ADD_REVIEWER_TAG)) {
       fixedChangeMessage =
           fixCodeOwnersOnAddReviewerChangeMessage(fixProgress, originalChangeMessage);
     }
@@ -1194,6 +1210,9 @@
     /** {@link RefNames#changeMetaRef} of the change that is being fixed. */
     final String changeMetaRef;
 
+    /** Tag at current commit update. */
+    String tag = null;
+
     /** Assignee at current commit update. */
     Account.Id assigneeId = null;
 
diff --git a/javatests/com/google/gerrit/server/notedb/CommitRewriterTest.java b/javatests/com/google/gerrit/server/notedb/CommitRewriterTest.java
index f316660..19c2bcf 100644
--- a/javatests/com/google/gerrit/server/notedb/CommitRewriterTest.java
+++ b/javatests/com/google/gerrit/server/notedb/CommitRewriterTest.java
@@ -34,6 +34,7 @@
 import com.google.gerrit.entities.RefNames;
 import com.google.gerrit.entities.SubmitRecord;
 import com.google.gerrit.json.OutputFormat;
+import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.ReviewerStatusUpdate;
 import com.google.gerrit.server.notedb.ChangeNoteUtil.AttentionStatusInNoteDb;
@@ -1603,19 +1604,20 @@
     accountCache.put(duplicateReviewer);
     Change c = newChange();
     ImmutableList.Builder<ObjectId> commitsToFix = new ImmutableList.Builder<>();
-    ChangeUpdate addReviewerUpdate = newUpdate(c, changeOwner);
+    ChangeUpdate addReviewerUpdate = newCodeOwnerAddReviewerUpdate(c, changeOwner);
     addReviewerUpdate.putReviewer(reviewer.id(), REVIEWER);
     addReviewerUpdate.commit();
-    ChangeUpdate invalidOnAddReviewerUpdate = newUpdate(c, changeOwner);
+    ChangeUpdate invalidOnAddReviewerUpdate = newCodeOwnerAddReviewerUpdate(c, changeOwner);
     invalidOnAddReviewerUpdate.setChangeMessage(
         "Reviewer User who was added as reviewer owns the following files:\n"
             + "   * file1.java\n"
             + "   * file2.ts\n");
     commitsToFix.add(invalidOnAddReviewerUpdate.commit());
-    ChangeUpdate addOtherReviewerUpdate = newUpdate(c, changeOwner);
+    ChangeUpdate addOtherReviewerUpdate = newCodeOwnerAddReviewerUpdate(c, changeOwner);
     addOtherReviewerUpdate.putReviewer(otherUserId, REVIEWER);
     addOtherReviewerUpdate.commit();
-    ChangeUpdate invalidOnAddReviewerMultipleReviewerUpdate = newUpdate(c, changeOwner);
+    ChangeUpdate invalidOnAddReviewerMultipleReviewerUpdate =
+        newCodeOwnerAddReviewerUpdate(c, changeOwner);
     invalidOnAddReviewerMultipleReviewerUpdate.setChangeMessage(
         "Reviewer User who was added as reviewer owns the following files:\n"
             + "   * file1.java\n"
@@ -1624,17 +1626,17 @@
             + "\nMissing Reviewer who was added as reviewer owns the following files:\n"
             + "   * file4.java\n");
     commitsToFix.add(invalidOnAddReviewerMultipleReviewerUpdate.commit());
-    ChangeUpdate addDuplicateReviewerUpdate = newUpdate(c, changeOwner);
+    ChangeUpdate addDuplicateReviewerUpdate = newCodeOwnerAddReviewerUpdate(c, changeOwner);
     addDuplicateReviewerUpdate.putReviewer(duplicateReviewer.id(), REVIEWER);
     addDuplicateReviewerUpdate.commit();
     // Reviewer name resolves to multiple accounts in the same change
-    ChangeUpdate onAddReviewerUpdateWithDuplicate = newUpdate(c, changeOwner);
+    ChangeUpdate onAddReviewerUpdateWithDuplicate = newCodeOwnerAddReviewerUpdate(c, changeOwner);
     onAddReviewerUpdateWithDuplicate.setChangeMessage(
         "Reviewer User who was added as reviewer owns the following files:\n"
             + "   * file6.java\n");
     commitsToFix.add(onAddReviewerUpdateWithDuplicate.commit());
 
-    ChangeUpdate validOnAddReviewerUpdate = newUpdate(c, changeOwner);
+    ChangeUpdate validOnAddReviewerUpdate = newCodeOwnerAddReviewerUpdate(c, changeOwner);
     validOnAddReviewerUpdate.setChangeMessage(
         "Gerrit Account who was added as reviewer owns the following files:\n"
             + "   * file1.java\n"
@@ -2249,6 +2251,13 @@
         .collect(toImmutableList());
   }
 
+  protected ChangeUpdate newCodeOwnerAddReviewerUpdate(Change c, CurrentUser user)
+      throws Exception {
+    ChangeUpdate update = newUpdate(c, user, true);
+    update.setTag("autogenerated:gerrit:code-owners:addReviewer");
+    return update;
+  }
+
   private ImmutableList<String> commitHistoryDiff(BackfillResult result, Change.Id changeId) {
     return result.fixedRefDiff.get(RefNames.changeMetaRef(changeId)).stream()
         .map(CommitDiff::diff)
diff --git a/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard_html.ts b/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard_html.ts
index 192a812..b7b4d9c 100644
--- a/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard_html.ts
@@ -51,13 +51,13 @@
     div.section {
       margin: 0 var(--spacing-xl) var(--spacing-m) var(--spacing-xl);
       display: flex;
+      align-items: center;
     }
     div.sectionIcon {
       flex: 0 0 30px;
     }
     div.sectionIcon iron-icon {
       position: relative;
-      top: 2px;
       width: 20px;
       height: 20px;
     }
diff --git a/polygerrit-ui/app/elements/core/gr-router/gr-router.ts b/polygerrit-ui/app/elements/core/gr-router/gr-router.ts
index 8e70eb9..f0cff85 100644
--- a/polygerrit-ui/app/elements/core/gr-router/gr-router.ts
+++ b/polygerrit-ui/app/elements/core/gr-router/gr-router.ts
@@ -178,7 +178,7 @@
   CHANGE_ID_QUERY: /^\/id\/(I[0-9a-f]{40})$/,
 
   // Matches /c/<changeNum>/[*][/].
-  CHANGE_LEGACY: /^\/c\/(\d+)\/(.*)$/,
+  CHANGE_LEGACY: /^\/c\/(\d+)\/?(.*)$/,
   CHANGE_NUMBER_LEGACY: /^\/(\d+)\/?/,
 
   // Matches