Descriptive Problem Summary:
Banning an IP address for the duration of the current session didn't actually work. It was all-or-nothing.
Numbered Steps to Reproduce Problem:
1) Ban an IP address.
2) Set the ban to expire at the end of the session.
The IP address would be banned, but the ban would expire.
The ban was ineffectual if set to expire after the session.
When does the problem NOT occur?
When the ban is permanent.
Set a permanent ban, but add a note to remove it later.