Possible Bug or am I doing something wrong

For whatever reason, only one side of this symmetrical object is baking its normals correctly.

I believe it has something to do with the cage mesh because cageless bakes work fine. Any insight would be appreciated. test.blend (11.8 MB)

note: this is from a larger .blend where the normal bakes were taking +30 minutes for no discernible reason, so I copy/pasted them in a new scene to troubleshoot. Now I find myself troubleshooting this :mad: