Welds keep getting messed up after testing

I am currently trying to make a shield that is welded to the player character. Everything was fine until after a while my welds kept being messed up.
I test and its fine. I stop the test and then test again, however this time some parts aren’t on the character. The only way to fix this is to stop testing, delete the welds and do them again.
I have tried naming all parts differently, that did not work at all.

I have tested this in an actual server and the welds are broken there too.

Are you using welds or weld constraints?