>>289642473
>but likely the bone positions of your neck/chest are causing the IK to move your chest bone for some reason.

Sounds like it may be the cause, unsure what else is doing it.
What would be the simplest way to troubleshoot or try and fix this? I mean my armature is a standard CATS fix'd generic rig and it works just fine other than this chest puffing. should I move the chest/neck bones like forward in my armature so they are closer to the front of my body mesh? they are fairly centered right now