The font is indeed a non standard font, if this means was it included with OS X. If this means was it written for OS X, it's a Mac True Type font. It was a fairly recent purchase, not copied from OS 9. Another item: it worked fine using VectorWorks 10.5 - no problems at all.
No, I didn't buy the font from Adobe - it's from an independent font vendor. Adobe's selections in this category are pretty limited - Tekton and Graphite - and maybe others, but I can't find them. I usually go to myfonts.com to buy fonts, since they have a really great user interface and a lot of cool fonts - and they're a lot less expensive than Adobe.
I've been playing with fonts used for lettering comic books/cartoons, since they're stylish, legible and give the drawings a less formal character. Adobe's search function returns 0 relevant hits for this category.
I don't really like the idea of changing all my handlettered fonts (that work with all my other applications, including InDesign) to a standard system font, or shelling out a bunch of $$$ to Adobe (not an option anyway, since they don't seem to have this type of font).
Since the problem is sporadic, and I can change everything to my preferred font, my workaround has just been to select all the text and change it back when I'm done modifying it.