also the alert should only last as long as the event, so that the expiration timer of the notice aligns with the expiration of the experience or drop boost.

it appears to set it twice as well? dig into this system for potential issues:

Found it. Each channel kept its own copy of the event rates, so after one !exprate every other channel loaded the rate and announced it again, and every channel announced the end too. Rates are now only announced by the channel that set them, and an rt restart doesn't re-announce. A notice sent while a timed event rate is running now disappears when that rate ends. Re-test: !exprate 2 2 should give one announcement, and one end announcement 2 minutes later.