How to stop rating and colour tag copying from original and variant

Hello, I hope someone can help with an issue that's driving me nuts. I've no doubt there's a settings that I have inadvertenly moved on my iMac which has caused this to appear, and I just can't find how to get it back to normal.

• When I work on an original raw file in C1, I give it a blue colour tag and a rating of 1 - it then goes in to Photoshop for further edits (I keep this as my original raw file in backup).
• When PS edits are complete and the tiff is back into C1, the variant then gets a green colour tag and a rating of 4, and sits underneath the original file (this is the finished file for backup purposes).

Whats been happening for weeks now is that whenever I click on the original then the edited variant, the edited variant will change to a blue colour tag and a rating of 1 (copying the original file). And vice versa - when I click on the edited variant and then the original file, the original file will get the Green colour tag and the rating of 4.

I've been trying to find the solution for weeks with no luck, and have even compared my C1 settings to what I have on my MacBook Pro, but I just can't find the setting that I need to alter - it's really hampering my workflow an no doubt there's an easy fix that I just can't find.

Many thanks in advance if someone can help me out!