diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
index 807d0cd..c6d2ee0 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
@@ -1252,9 +1252,13 @@
     this.$.fileList.collapseAllDiffs();
     this._patchRange = patchRange;
 
+    const patchKnown =
+      !patchRange.patchNum ||
+      (this._allPatchSets ?? []).some(ps => ps.num === patchRange.patchNum);
+
     // If the change has already been loaded and the parameter change is only
     // in the patch range, then don't do a full reload.
-    if (!changeChanged && patchChanged) {
+    if (!changeChanged && patchChanged && patchKnown) {
       if (!patchRange.patchNum) {
         patchRange.patchNum = computeLatestPatchNum(this._allPatchSets);
         rightPatchNumChanged = true;
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts
index 877bdd6..3d51ac6 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.ts
@@ -1633,6 +1633,13 @@
     assert.isTrue(reloadStub.calledOnce);
 
     element._initialLoadComplete = true;
+    element._change = {
+      ...createChangeViewChange(),
+      revisions: {
+        rev1: createRevision(1),
+        rev2: createRevision(2),
+      },
+    };
 
     value.basePatchNum = 1 as BasePatchSetNum;
     value.patchNum = 2 as RevisionPatchSetNum;
@@ -1661,6 +1668,13 @@
     element._paramsChanged(value);
 
     element._initialLoadComplete = true;
+    element._change = {
+      ...createChangeViewChange(),
+      revisions: {
+        rev1: createRevision(1),
+        rev2: createRevision(2),
+      },
+    };
 
     value.basePatchNum = 1 as BasePatchSetNum;
     value.patchNum = 2 as RevisionPatchSetNum;