Sharing transition rule it will be Dirty when AnimBP opens.
When AnimBP is open, "if(BoundGraph->GetOuter () != Node)" is true in FBlueprintEditorUtils::UpdateOutOfDateCompositeWithOuter, BoundGraph->Rename is executed.
1. Create AnimBP.
2. Add three AnimStates and connect from State1 to State2, State3.
3. Sharing transition rule of State1-2 and State1-3.
4. Compile and save AnimBP.
5. Close and reopen AnimBP. At this time, AnimBP will always be dirty.
Attached snap shot of repro step.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-53499 in the post.