I'm not exactly sure of the cause of fetch errors, but they do happen occasionally. I've looked it up but there doesn't seem to be an explanation or solution, and it happens to many people.
I'll do some extra research into it and try to make sure its effects are minimal or eliminated for v2.
V2 progress is on a hold while I work on hlf polls, which I might promote in clf. It's good though because I've found a lot out from the hlf polls project and it all helps to make the next clan logger as good as it can be.
I hope the logger is really helping people organize their ranks as is for now anyway