fail2ban service doesn't work correctly when hostname starts with number

[Ugubok]

This is my hostname: 20073.s.serverhost.name
In /var/log/auth.log typical line looks like that:
Aug 15 21:44:42 20073 sshd[1230]: Received disconnect from 127.0.0.1: 11: [preauth]

fail2ban service recognizes hostname like a part of date, so in /var/log/fail2ban.log (when loglevel=DEBUG) we got:
<...>
2016-08-15 21:44:42,235 fail2ban.datedetector [1116]: DEBUG Matched time template (?:DAY )?MON Day 24hour:Minute:Second(?:\.Microseconds)?(?: Year)?
2016-08-15 21:44:42,235 fail2ban.datedetector [1116]: DEBUG Got time 1187203482.000000 for "'Aug 15 21:44:42 2007'" using template (?:DAY )?MON Day 24hour:Minute:Second(?:\.Microseconds)?(?: Year)?

For this reason fail2ban doesn't ban attackers (it concerns at least for sshd rules and other services, which log in /var/log/auth.log)