Wow, okay, I'm an idiot. The bits of text in the margin between panels—"©2000 by Alun Clewe" (which as discussed previously I've been changing to "©2021-2023") and "www.soupcomic.com"—were originally in Helvetica, a font that I apparently somehow had access to when I first created this strips but don't anymore. I've been changing them to Arial, which I've been doing the hard way, by selecting the text in each object and manually changing the font. But when I open the old strips in Adobe Illustrator, I've been given the option to replace missing fonts, which is much faster and easier. I haven't been doing that, though; I've just been closing that window when it pops up. Why? Again: I'm an idiot. Anyway, I'll be doing it that way from now on. (At least until I get through the backlog of old strips and don't have to do this anymore.)