The LDAP authentication failure did not appear in version 8.5.0
It appeared originally at version 8.4.2 and I was the first person to report the issue that I know of.
Due to the lack of involvement, the issue persisted from 8.4.2 to 8.5.0.
So maybe looking a bit further may help someone to find the issue.
And again, if someone suggests feasible, reasonable, tests to make, I will make them, as I have been doing so far.