As of today, Pending closure is based on the following procedure:
Red Hat Support engineer commits a manual comment and, in Issue Tracker, he
manually sets the case status to 'Pending closure' Often at the same time the
technician will make a comment. This could generate 2 notifications under
today's logic; one for the comment, a second for the status change to Pending
Closure.

If a comment and status change is made to flip to Pending Closure, the system
must send only one notification to the customer that includes the comment and
the pending closure status change

If the comment is committed, then the status change is committed (or vice
versa), the system must detect that condition and send only one notification to
the customer that includes the comment and the pending closure status change

If a status change is made to Pending Closure and no comment is made within the
notifications time period, send a generic email saying that the case has been
moved to pending closure. Text to be provided in update to JIRA.