In looking into another issue with mu4e, I decided to examine the log in ~/.mu/log/mu.log to see if anything was causing an issue, and I found thousands of lines saying:
[CRIT] mu_str_escape_c_literal: assertion 'str' failed
I updated mu to the latest HEAD, reindexed, and ran for a day. Checked the log again, and there are over a hundred of these critical alerts, so the latest code is generated these alerts. I am not sure what they are referring to or whether they are an issue.
Cheers,
Brian