Character rig refuses to simulate physics/stay 'awake'

I’m attempting to make a spooky Halloween death animation where your character gets ripped in half. What I’m doing is taking a clone of the player (client-side model), attaching the left foot and left hand to separate tendrils of this tendril beast (client-side model) using ball sockets (client-side constraints). Unless I’m mistaken - all of this means the player has network ownership of everything. After 1 second, the player model’s Waist constraint is destroyed. The issue is that the lower body simply ‘goes asleep’ or stops simulating physics instantly upon separation.

In October 2023 this exact code worked fine, but this year it is behaving in strange ways that I can’t figure out. I’ve tried using two separate models (player torso + legs). In that case, the lower body half works just fine until I detach them (the 2 models are the exact same, just minus the visible body parts). I’ve made sure everything is NOT Massless, etc. I even tried replacing the Waist constraint with a Spring. Even if I disable the spring or set the MaxForce to zero - the two body parts stay attached anyway.

Does anyone have any clue as to what would cause this group of parts to simply stop using physics like this? Video below depicting the lower body/legs just cease to move upon separation. Look closely - the legs just freeze. The red outlines are parts which are ‘awake’.