(1)
Previously (before v 2.2.4 - ZBX-8230) it was possible to at least find some details in zabbix_server.log (in production users usually use DebugLevel=3) that hosts were in maintenance.
And I know cases when users indeed check the log file when need to make sure maintenance activities.

Currently - no any way at all to make sure why this or that events don't generate alerts.
Also, we know that when timer takes a host out of maintenance it creates the same event as last event created during maintenance (this point requested to be documented in ZBX-8390).
This behavior implemented in "generate_events" function (timer.c).

I have a question - suppose after a week (note - my memory limited by 3 days only) of a host maintenance I investigate host's events and I cannot understand why for this particular problem event zabbix didn't send an alert?
I completely forgot about the maintenance a week ago, or I didn't know about it at all because someone else configured it and later it was modified or deleted.

(2)
Also I have another puzzle question - why here are two Ok|Problem events in a row, and for 2nd such event time stamp I don't see values in items history?

To resolve all this and provide clear info to zabbix users I suggest to implement a feature that:
for events which were created during maintenance on Monitoring -> Events page in a "Actions" column users will see something like "Maintenance, skipped" or there will an icon with a tool-tip, which also could include full maintenance name.

It should help to understand why alerts were missing AND!!! will provide a hint that next the same Ok|Problem event above generated by timer according to internal zabbix routines ("generate_events" function).
Then it will much more clear for end users what happened.

Where it could stored - I don't know. The "events" table don't have suitable columns.
I guess currently numbers (if there were alerts) for the "Actions" column taken from "alerts" table.
Maybe we could store something to the "alerts" table and then display it in a special way?