Firstly, I’ve done an md5 check, so I know that my Black Mesa archive isn’t incomplete. Also, I’ve tested this at several resolutions and aspect ratios (I normally run at 1920 x 1080), so it’s not a problem with that, as far as I can tell.
Anyway, one thing I noticed when I booted up Black Mesa a second time, a few days ago, was that my load menu was scrambled, and has stayed that way since (but the other menus, including the new game and save ones, are fine). The screenshots are clustered in a little scroll-down box in the top left-hand side of the menu, with three listings of “Label” to the right, as you can see here:
I can still load, but this is highly irritating, since it means that I sometimes have to guess if I need to revert to an earlier save for whatever reason. I’m not sure if anyone else has had this issue, but I haven’t been able to find any other posts on it (although my search might not have been thorough enough).