Motor6d animation not working until player comes close

My game did not have this bug at all, and other games have never seen such a bug, and it seems that the bug was caused by an update a few months ago. Specifically, for example, when player1 approaches another player2, the motor6d animation of player2 plays normally. But when it dies or the script runs again, this happens again. And this will get rid of the animation and the gun’s parts will not move, eg the magazine or slide. The reason why this is the worst problem of Roblox seems to happen frequently in FPS games like a few other games such as Counter Blox, my game. I hope it gets fixed soon. If you have a solution, please reply, thank you.

Look at the video, it looks pretty serious
My game:

Counter Blox: