Google Photos deletes copy and original on device

I’m facing a very strange issue with the Google Photos app. Every time I copy an image with “copy in folder” (specifically not “move in folder”) and then delete either the copy or the original image, both are gone.
In the trash only one image remains after that. If restored both images are back.

This is not the behavior that I natively expect. When I delete one image, I want the other to still remain in its folder.
I have searched for a solution myself, but was unsuccessful. (I only found unanswered threads like this one.)

My question is: Why is this happening and is there a way to change this behavior?

Google Photos version: (newest to date)
Android version: 10