When hq-server database contains a large number of alerts (here, 400000+ alerts have been fired and db is set to store these alerts for a month) , then navigating to the Ops center page loads the main page frame but does not load the frame with the list of alerts. Waited for several minutes for the page to load and it kept spinning.
Further tests will be conducted to determine the consistency of this bug and when it times out. Meanwhile, filing it to start tracking the issue.
2 attempts till now:
Waited for 10 mins, did not load or time out
Waited for 45 mins (when server was under load from alerts firing), alert list on ops center did not load and did not time out