Oh phew! I've always aimed for five nines reliability in my career so hearing half a percent (one nine) while small is a big deal for my rep. I would encourage you to keep torture testing redbean. Let me know if you spot any opportunities for improvement!
This was testing against the old version (1.4) a while ago. I retested using the new version and have 0 errors.
However, that said, I also upgraded my ethernet switch since then, so possibly the original TLS errors were due to simple dropped packets.