I haven’t had this exact issue but I’ve had issues in the past where UMG slate widgets being destroyed would cause bad things to happen on the render thread. I got around these (and made an accepted pull request for code in a few places regarding this) by adding a check inside the crashing function that makes sure the target object doesn’t have the flags RF_Unreachable or RF_PendingKill set. I don’t have access to my engine source at the moment so I can’t figure out where it would be best to make this addition, but hopefully this info is enough for you to find out where to place this check, and hopefully, make a pull request on github.