I consider this bug quite severe as it may break working setups after an update.
The corresponding bug report for Ubuntu might be this one: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1034261 It is the same bug reported on the autofs mailing list here: https://www.spinics.net/lists/autofs/msg02389.html Apparently, it has been introduced in the transition of autofs from 5.1.7 to 5.1.8. A fix has been posted here: https://www.spinics.net/lists/autofs/msg02391.html and again https://www.spinics.net/lists/autofs/msg02434.html
