The libevent bug described in https://github.com/libevent/libevent/commit/5ff8eb26371c4dc56f384b2de35bea2d87814779 was already patched in release-2.1.9-beta, with cherry-picked commits 5b40744d1581447f5b4496ee8d4807383e468e7a and b25813800f97179b2355a7b4b3557e6a7f568df2.
There should be no side-effects by re-applying the workaround on an already patched version of libevent (as is currently done in master for people running libevent between 2.1.9 and 2.1.12), but it is best to just set the correct version number to avoid confusion.
This will prevent situations like e.g. in #27909 (review), where a reverse workaround was incorrectly applied to the wrong version range.