Ok. I'll stop doing that with B4A.
I have narrowed it down even more. When a B4A project is running from a Dropbox folder, any attempt to save a layout with a filename with uppercase letters will show the filename with uppercase letters in B4A Files Manager and actually save it to disk with those uppercase letters. However, when run from outside Dropbox, that will still show the filenames with uppercase letters in B4A Files Manager, but will actually save them to disk with no uppercase letters.