We need to fix udev rules for that then.
Thanks for confirming.
Can you add:
SUBSYSTEM=="gpio*", PROGRAM="/bin/sh -c 'chown -R root:osmc /sys/class/gpio && chmod -R 770 /sys/class/gpio; chown -R root:osmc /sys/devices/virtual/gpio && chmod -R 770 /sys/devices/virtual/gpio; chown -R root:osmc /sys/devices/platform/soc/*.gpio/gpio && chmod -R 770 /sys/devices/platform/soc/*.gpio/gpio'"
to a new file called /etc/udev/rules.d/996-fix-gpio-mem (chmod +x)
and let me know if it works
Sam