creachr
All of these avatars of mine are unable to generate impostors, across many of bases.
https://vrchat.com/home/avatar/avtr_60376225-9215-4f5d-a699-9293ed8e7a7a
https://vrchat.com/home/avatar/avtr_d7a97b4f-69df-4126-9342-8086a3137e3d
https://vrchat.com/home/avatar/avtr_3791b06e-4ec6-41e6-adf4-f7fb94016576
However, these that I uploaded last month seem to work fine.
https://vrchat.com/home/avatar/avtr_ef4533ef-1270-4549-9065-93c128cf22c4
https://vrchat.com/home/avatar/avtr_c7103a64-b573-4c41-8631-3756c3ad551a
I have updated the SDK on many of my projects last month, and this is the only reason I can think of for this happening.