Maintenance for the week of April 22:
• [COMPLETE] Xbox: NA and EU megaservers for patch maintenance – April 24, 6:00AM EDT (10:00 UTC) - 12:00PM EDT (16:00 UTC)
• [COMPLETE] PlayStation®: NA and EU megaservers for patch maintenance – April 24, 6:00AM EDT (10:00 UTC) - 12:00PM EDT (16:00 UTC)
It doesn't have a cooldown so won't appear in S'rendarr
You'll need to log your tests and check ultimate gain under resources. If you're just looking for a way to track procs in game, I just watch my ult pool fill up like crazy and can tell.