We’ve discovered a significant issue that maybe some other users have been experiencing:
When you reference in a rig and then ‘group’ it in the scene (for organisation or hierarchy manipulation for export etc), you will get a giant list of reference edits that given enough rigs in your scene will make the scene unable to open.
It seems to be doing a connectAttr to nearly every node in the rig, and then a subsequent disconnectAttr.
If you reference in the rig and instead create an empty group first and then parent the rig under that, it doesn’t add any of the reference edits, except the one line for parenting.
It does appear to be something specific to mGear rigs from my limited testing so far.