I have same problem now on official siptah server, the dancer thrall named Dances-with-bears refuse to attack anything, just fists after some hours, there is no way i have found to fix this, just have to wait for server restart. I have tried equip all new clothes, all new weapons and food… I have also tried to unfollow and have another thrall to follow and back again but she not attack with weapons. It seems like she just tired of fighting and just want to dance, i dont blame her really, but would be nice to have a fix cause its a good fighter too.
equip Dancer
lets follow
fight
after some time dancer stop fighting only show up empty fists
Wait for server restard to fix till the bug repeats.
I have always 3 stacks of gruel and Black Bruargh’s Fury shield and legendary Momentum weapon, so full inventory before it happen yes, but i dont know if that is the reason, i do that also with other thralls, never happen there as far as i remember.