[Build 751]
The IK Follower component for helping keep world-space particles properly positioned does not take the scale of its parent transforms into account when calculating position offset.
Transforms with IK Follower that are children of typical bones like "Right wrist" (in a typical skinned mesh hierarchy where the Armature transform has a scale of 100) will appear to have their offset removed and translated back to the Right wrist bone at runtime. But in reality the offset IS being kept but scaled down by .01.
A workaround to make VRC_IK Follower work in VRChat at the moment is to create an intermediate transform in between followed bones (Right wrist, etc.) and offset transforms with IK Follower with a scale that compensates for the hierarchy. (Create a child of Right wrist, drag it outside the avatar to make it a root level transform, change its scale to 1/1/1, and re-insert it as a child of Right wrist. Then add offset IK Followed transforms as children of this transform.)