Hi ,
I am leaning more towards this being intended behavior. Mainly because you CAN trim the length of a montage anim clip by setting start and end time. Say you have an animation that is 5 seconds long. You set start and end to 1 and 3 seconds. Then you extend the animation to 7 seconds long, the engine can’t know what section you want to use now. And if you still wanted the 1-3 section, then the engine would probably be messing that up if we implemented the functionality you’re looking for.
We’ve added things like this in the past and almost always roll them back (usually something with sequencer trying to adjust for new content. things like that).
If you think I’m completely wrong here, let me know. I’m open to hearing an alternative point of view.