Your comments

I will be glad to send you two files. It should be noted that it doesn't happen *consistently*! I've just had it happen four or five times during the past week, and I've been able to address the problem by rebooting. (Presumably this is the only manner of what would be analogous to laptop "clearing cache".) Please direct my pea brain to a manner of sending you the files. Else you may follow this example:

(1) Fetch the source code of

(2) Fetch the source code of

(3) Edit the former in TexTastic

(4) Note the link at the bottom of the page to "copyright.htm". — make it a local link.

(5) View 000.htm — take the link to "copyright.htm" — exit view — (thus returnining to edit "000.htm") — view again — see whether it happens.

Perhaps this could be done via "Open in..." — heck, maybe it already can! I've been so lazy, I haven't even tried. It was just an idle thought,  ecause I can perform a similar operation using BBEdit on my laptop... Oh, well.

I'm not sure what you mean, but, when I'm editing "x.html" and select the eyeball icon, I often find that the linked file ("y.html") is displayed instead of the file being edited ("x.html") even though the file path for "x.html" is being displayed at the top of the screen. FWIW, both are local files.