Creating an action on the armature lags the file. [2.82]

So I created 4 rigged characters for animation, all stemming from the 1st rig, but all in their own files respectively. I’ve noticed that when adding 1 keyframe, which in turn creates an armature action, it freezes blender for about 10 seconds to add it. Then when I try to launch the file later when saved, it either takes a bit to open or it just crashes blender.

The rare exception is the first character I rigged, which is where my base rig came from. When adding his action, there is no lag whatsoever, so clearly something is wrong with the other rigs. The problem persists when trying to import the rigs to another file, so its not something with the file, but with the rig. It is perfectly fine until I add a keyframe, then it freezes. I was wondering somehow if there were some sort of artifacts left from when I was transferring the rig, but I couldn’t find anything.

If anyone knows anything about this please help.

UPDATE:
I tried deleting all the mesh on a rig and tried again and it worked fine, so something in the mesh is causing it.

SOLVED: It was the bezier curve I used to rig the spine-IK. It had an armature modifier when it didn’t need to. My theory is that it was creating some sort of dependency loop that was short-circuiting the program.