Recently we are facing a problem on our Zabbix Server where the configuration syncer process crashes and the service keeps restarting.
We caught several cases that during the service restarting, the problem 'cannot read (alerter|LLD) manager service request' kept showing on which made the service restart again in loop until the error message vanished and the service went up completely.

We did not made any update/upgrade recently on Zabbix Server neither on RDS to begin theses crashes...