Email Bans Disappearing,,, AGN

The banned email addresses have disappeared from the ban control panel again, why does this keep happening? they may last a month, then they may last 6 weeks, but they disappear, its a bit of a pain as the email addresses have to be inserted agn one by one.
This issue was brought up a couple of months ago by myself and others but never got answered or resolved.

https://help.forumotion.com/garbage-f4/only-topic-banned-members-t14200-30.htm#77940

https://help.forumotion.com/other-problems-f46/banned-email-addresses-disappeared-t19894.htm#106870

cheers

Iv had this problem a few times with email address and ips i just add them again

I re-add them but its a pain when you got 50+ to keep adding manually one by one, i know it only takes abt 10-15 mins but that still dont answer why it happens.