Hardware IDs keep getting recreated on Macintosh clients

I recently was assigned responsibility for managing the desktop end of our Symantec Endpoint Protection installation (v. 12.1.4).  I have our Windows machines under control, but I seem to be having an issue with the Macintosh end.

I've noticed that Macintosh machines will occasionally pop into our default group.  When I move them into the Mac group I created, I can see a previous entry for them.  I'm guessing this is because the Hardware ID is getting recreated somehow, but I can't find any documentation of HWID issues on Macs.

Has anyone else experienced this?  Can I at least get a decent disection of Mac installations so I can try to troubleshoot this myself?

Thanks!

/Mike