This is NOT a request about the seconds set for this trigger. The default setting uses {$SYSTEM.FUZZYTIME.MAX} which is 60s and it is OK/FINE!
https://git.zabbix.com/projects/ZBX/repos/zabbix/browse/templates/os/linux/template_os_linux.yaml

The problem is flapping when the system time is out of sync and close to trigger check value. In my screenshot the {$SYSTEM.FUZZYTIME.MAX}  was set to 30s

The problem is that when system time difference is near 30s. Zabbix starts receiving values like 29s, or 31s depending on network conditions. This is causing flapping of this trigger.

Please introduce hysteresis! -> https://blog.zabbix.com/no-more-flapping-define-triggers-the-smart-way/1488/
For example, introduce {$SYSTEM.FUZZYTIME.MIN} in this template and turn off trigger when system time difference is < {$SYSTEM.FUZZYTIME.MIN}

Again, this issue is NOT related to value of {$SYSTEM.FUZZYTIME.MAX}. It is related to flapping condition for trigger! I tried to make a bug report for this issue. But it was closed with a strange comment unrelated to the issue I reported.
https://support.zabbix.com/browse/ZBX-18794