There could be another bit of weirdness here too. I had a file with spaces in the filename and a double hyphen. Like this:
jonah and the whale -- dore illustration.jpg
and this file was repeatedly deleted and copied every single rsync attempt.
Generally, I do not use spaces in my filenames. My primary OS is Linux, at the command line, and spaces are anathema. I have to escape those things all the time. If you are using a GUI only with a GUI file manager, you can use spaces to your heart's content and not notice anything. If you are working on the command line much, you learn to hate spaces in filenames.
These files came from a CD of clipart and this appears to be the only one containing a double hyphen. I don't know why it causes issues, but I renamed it, and all the others to not give me grief. I'll run some tests on it later.