I've used items with this shader before hand and was always able to film videos or sit in an MMD with them. But while they look normal on camera on POV, cameras and mirrors are rendering these particles as a giant bright emissive square. Has an update broke this? while I've only tested this on PC, I've used the same shader on quest so I would assume it applies there as well. I'm using a trail effect with the particle shader. This was working normally not too long ago. I just updated VRChat today.
Edit
My friends are saying they see it normally in mirror and camera and when I look at other people using it it works. It seems to be only happening on the personal user level?