Tor is getting stuck boostrapping sometimes (not reaching the 75% threshold)

We use a tool called relaybw to measure the bandwidth of particular relays, kind of simulating sbws, in order to debug bandwidth measurement issues. Sometimes this tool breaks because tor gets stuck bootstrapping. I attached the info.log of one of those incidents. The configuration options for tor we use can be found in defaults_tor.py.

Looking at the info log, I believe that this problem is not just related to that particular relay bandwidth measurement tool we use. Rather, I'd expect the underlying issue visible in other applications as well.

Another note: while that particular log shows Tor 0.4.8.16 used, we saw this issue as well when using the latest code on main.