Mute on one track enables mute on other (unlinked) tracks as well

Hi,
I have a weird issue. As stated in the topic: In a project when I mute one track, it enables mute on other (unlinked) tracks as well. They are not linked and Mute is excluded from link anyway.
I’ve made a Screen capture to show the issue. I’m not sure if this is a bug or that I’m overlooking something.

Thanks in advance for advice