I configured a Raspberry Pi 2 with a button. I have a script in python, which will call a command, if someone press the button. The command doing a sip phone call to a phone server (cisco communication manager). This works fine. The python script to watch the GPIO and call the command should be running automatically. So I configured it as a system daemon with systemctl. Runs fine. But unfortunately at some times the command is calling, but nobody has pressed the button. I see sometimes that CRON is running before the command is called. But the crontab is empty. Sometimes there is no entry in syslog before the command is called. What can it be?
Python is 3.5,
Linux raspberrypi 4.14.34-v7+ armv7l GNU/Linux
the called command is
sipcmd from https://github.com/tmakkonen/sipcmd