There is no guarantee that depsgraph is ran between two undo steps, so when re-using an existing data-block we should never wipe completly its recalc flags, but instead complement them with new ones from accumulated 'storage' as needed.
There is no guarantee that depsgraph is ran between two undo steps, so when re-using an existing data-block we should never wipe completly its recalc flags, but instead complement them with new ones from accumulated 'storage' as needed.