Mea Culpa
I seem to have rushed to deliver the background fetcher. While it worked well "interactively", it seems it was not very robust to external events/failures (would stay stuck on absence of internet, on mac getting out of hibernation, ...)
I promptly released 3.0.1 that de-activated the background fetcher by default.
Now I think I have fixed the issues. The background fetcher has been running on my machine for a week without issues, or rather recovering properly following issues.
I'm releasing it again. 3.1.0 is just the re-enabling of what should have been working in 3.0.0
Have fun