video and audio lost the link after 1 clip unlink

I have version 17.1.1 build 9, when I work on a new video today, I have to unlink 1 clip and replace it with another audio track of the same length, some how during this step, the other 4 clips that has video and audio track come up with the problem that when I select the video, the audio is not selected, but the link symbol on the bottom left still exist.
I do reboot the mac mini M1 once and try it again, it has the same problem.
I did try the link clips comment and the link symbol on top of the track, no luck.
Any idea what might be wrong, and how to fix this.
thanks.

Select both video and audio portions, right click, Link Clips.