When using Keep State together with an Animation Blueprint on a Character, the Anim BP will override the Keep State and transition over to the idle animation as the animation in the slot no longer responds to keep state.
This is a regression as it is working in 4.18
Results: The character reverts to normal animation (as set up in the animation blueprint) after the animation finishes playing.
Expected: The character stays in the last frame of the animation which is set to KeepState (this is the case if used on SkeletalMesh without anim bp)
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-59049 in the post.