Let's have a look at a screenshot I just made:
Until now, when viewing a page containing questions marked with an ‘interesting tag’, all questions got a nice, soothing yellow background to let me know that all questions contain interesting tags. I know this signal is redundant on a page where I view only questions containing at least one interesting tag, but I grew accustomed to the yellowish view.
However, I just visited SO again and clicked an interesting tag. To my amazement, not all questions got a yellow background, creating a sick zebra-like pattern in front of me, that looks distracting. I guess that something like this question's proposal got fulfilled, highlighting only questions that contain other interesting tags, but this looks confusing to me. As I can't find anything about this on Meta, it might as well be a bug.