Ah, I see, thanks for clarifying.
Since I use openHABian on my “developement/test”-RasPI-system, I’ve probably not stumbled over this serial permission issue.
Another idea is to check:
/etc/default/openhab2 to permit the required serial port, similar to:
EXTRA_JAVA_OPTS="-Dgnu.io.rxtx.SerialPorts=/rdev/zwave:/rdev/rfxcom"