I would add that I have had similar save problems (not sure if 206 onwards) and I'm definitely *not* using cloud saving.
I haven't been able to reproduce it. What seems to happen - I think - is that something gets out of sequence in the image editor - it's always related to this - , and one of the images goes AWOL , then it starts complaining it can't load the capx because the image isn't there - not sure because I've exclusively used project directories for the last month or so. It happened on 2/3 occasions for me, and I wasn't doing anything unusual at the time (e.g. external editor). Since using projects the problem has never happened again.