Wait for system to fully boot before running alerts
I've seen this several times on systems running 11.1-U4. The Alert system gets a little agressive and finds faults during long startups and long pool imports.
I think the fix is to make the Alert system not come up until the system completes booting as well as waiting to check status of the system during a failover event. The last customer I worked with we did some failovers and reboots, and we'd get erroneous messages like lagg0 was down (it wasn't down and hadn't been for almost 5 minutes) and zpool status was unknown. In both cases, it generated emails to the customer, and in the case of the zpool status, it generated a support suite ticket automatically due to proactive support.