The audio in the video clip is a U2 IEM recording, which explains the click. It's even the same feed, although different receiver types. Both are to two independent nomad jb3 (long since retired recorders!), which generally had a pretty good time clock from what I found.
When you're working with line recordings (like IEMs), you hear alignment issues much quicker than with audience recordings. I can hear when things are off by a couple samples. That hollow tunnel sound on vocals is unmistakable.
I have found that the internal clocks on decks are NOT consistent, and there is a slight curve. So if you align something from
00:00:00 - 00:30:00 - 99.999975%
00:30:00 - 01:00:00 - 99.999832%
01:00:00 - 01:30:00 - 99.999712%
I'm making up numbers but there is a change in the alignment. Now I don't know any time alignment program that can calculate the derivative, and make a proper alignment based on that. However, next best thing was to do it in intervals.
But like I said--audience recording mixing is much more forgiving. I typically align audience recordings on an hour basis, whereas much more closely on multiple line (iem/ald/sbd) recordings).
In any case, I get the $25 from the OP for providing a video