Alleged Family Members never disappear

I've noticed that Alleged Family Members on metrics seemingly never disappear.

Reported on Tor-relays: https://lists.torproject.org/pipermail/tor-relays/2018-November/016558.html

I also have the same issue: https://metrics.torproject.org/rs.html#details/490FB3FAAF8837407D94CA7E1DEF025DEF0F3516

My other relay has been offline for months (since July 2018) and it still displays as a family member.

Trac:
Username: Quake