Hi ,
The assert that you’re hitting is caused by the animation system trying to update the position of one of the bodies in the skeletal mesh. The assert is complaining that the transform coming in is invalid.
Unfortunately, there’s a number of reasons why this could happen and at this point it’s hard to determine who the culprit is. One way to help track this down would be to try and determine more info from your end. Is there any content that has changed since the beta that might be triggering this?
Are you able to isolate which skeletal mesh this is happening for? Is it always the same asset / animation?
If you manage to get a somewhat reproducible case you could upload your setup and we could have a look.
Sorry for the inconvenience, I realize this is annoying