The link suggests a number of things that might be wrong, it certainly has a valid file name ('move.ai'), I don't know if I'm using resource forks, but they really are very simple designs. I've unloaded & re-started AI, and noting else has accessed the files. It's the same size as the other .ai's in the folder.
I looked then at Keyboard combinations to troubleshoot sync issues, but they had no effect at all.
I have just created two more AI's, and exported them as .png. so far only one of the .ia's has sync'd and neither of the .png's have.