It's on the tin, Charlie.
Despite this not needing to be stated, guess I have to: you don't initialize heavy components like that every frame. Wait for calibration/scaling end, then refresh.
This bug was introduced some two-ish months ago, some time around you fellas posting about "fixing" cloth components not scaling with the avatars. Buzzer sound, I guess. Didn't have the time to report it back then.
Worse yet is the fact that this issue is global. It's not just the local player getting hit like it used to be with calibration pose animator re-runs, this one re-runs for
everyone
. Don't think I have to explain how unfun it is for 80 people in a public room to have their game be frozen for half a minute.
Test it yourselves with something heavy like these: avtr_ce52fd35-3f17-413e-b150-fce9319d48ca, avtr_791baeb5-48e1-4cfe-a3a6-10e486948f1c. Both of these are private, but I also have a public one with GUID beginning with "avtr_1e0dc4a6". Do a WHERE LIKE 'avtr_1e0dc4a6%' or something.