systemd restart timer doesn't reset trigger

[VinnieThePooh]

While execute command
$this->bbcode_second_pass_code('', 'systemctl restart timer')
trigger doesn't reset despite of appropriate messages in system log "timer stopped...timer started" for monotonic timer at least.
What I mean:
Let's say one set timer to 15 min and tries reset timer at 10 min. After input command from above timer doesn't reload time back to 15 min but continues current count in opposite of sequence
$this->bbcode_second_pass_code('', 'systemctl stop timer
systemctl start timer')
which one works as excpected