https://git.zabbix.com/projects/ZBX/repos/zabbix/browse/ui/app/controllers/CControllerProblem.php?at=refs%2Fheads%2Frelease%2F6.0#118

The problem that the code does not even assume that by requesting data for a trigger with a note that for each trigger it is necessary to return data for the host as well, it does not check later that no data for the host was returned for this trigger.

If for any reason the trigger's connection to the host was lost ( database inconsistency, for example), then when checking the availability report or problems on this trigger, the errors "Trying to access array offset on value of type null" will appear.