Steps to reproduce:

1. configuration zabbix_proxy.conf

   ConfigFrequency=60
   

2. create Proxy(Configuration -> Proxies)

   Zabbix proxy	Proxy mode
   Zabbix proxy	Active

3. create Host(Configuration -> Hosts)

   Host name	Monitored by proxy
   monitor by proxy	Zabbix proxy

4. create Item(Configuration -> Hosts -> Items (by Host "monitor by proxy"))

   Name	Type	key	Update interval
   agent.ping	Zabbix agent	agent.ping	3600

5. create Maintenance(Configuration -> Maintenance)

   (Maintenance tab)Maintenance type	(Hosts and groups tab)Hosts
   No data collection	monitor by proxy

6. wait to end of maintenance...

Result:
maintenance period: 2019/08/14 15:00〜16:00

2019/8/14 15:34 Host in maintenance
20190814_1534_Host_in_maintenance.png

2019/8/14 15:53 Host in maintenance are not counted in queue
20190814_1553_not_counted_queue.png

2019/8/14 16:00 Host immediately after maintenance are counted in queue
20190814_1600_counted_queue.png

2019/8/14 16:00 Host's latest data
20190814_1600_latest_data.png

Expected:
Should not counted in queue until next check.