I'm hanging my hat on my font issue being a rendering bug in macOS.
This has been happening since at least macOS 10.13:
The TextEdit document in the middle of
this screenshot is Lucida Fax 12.
The rendering above it is what I see when I hit command-P > Open in Preview with the document open; it's also what prints. (If I simply command-P the document on my desktop it prints correctly.)
The red text in the box is what I get when I annotate an open PDF. (I can't date the annotation problem, because I haven't used the feature in years, but I"m guessing that its occurrence coincides with that of the TextEdit problem.)
Summarizing, the middle example is rendered correctly while the top and bottom examples are not.
Bug report filed.
(10 seconds)
