"Problem is not suppressed" action condition in the actions may lead to missing notifications from Zabbix. Another affected user: https://www.zabbix.com/forum/zabbix-troubleshooting-and-problems/370741-problem-with-actions-after-maintenance-period-ends-zabbix-4-0-1

Steps to reproduce:

1. Configure Zabbix action with "Problem is not suppressed" condition for a host (use other default values, i.e. "Pause operations for suppressed problems" is enabled also)
2. Use "1 - 0" step to execute an operation continuously (e.g. execute a command every N minutes) 
3. Configure maintenance for 5 minutes for the host
4. Wait until maintenance is started for the host
5. Generete a test problem
6. Wait for 5 minutes until maintenance is ended for the host
7. Wait for some time

Result:
No operations/actions will be executed for the active problem after the maintenance

Expected:
Operation/escalation should be executed after the maintenance because problem is still active and not suppressed any more.