I have a UTF-8 encoded SystemD unit file that I want to autostart with 

SYSTEMD_SERVICE:${PN} = "my.service"

This causes the following exception:

Traceback (most recent call last):
  File "/build/lmp/build-lmp/tmp-lmp/work/intel_corei7_64-lmp-linux/lmp-factory-image/1.0-r0/recipe-sysroot-native/usr/bin/systemctl", line 351, in <module>
    main()
  File "/build/lmp/build-lmp/tmp-lmp/work/intel_corei7_64-lmp-linux/lmp-factory-image/1.0-r0/recipe-sysroot-native/usr/bin/systemctl", line 337, in main
    SystemdUnit(root, service).enable()
  File "/build/lmp/build-lmp/tmp-lmp/work/intel_corei7_64-lmp-linux/lmp-factory-image/1.0-r0/recipe-sysroot-native/usr/bin/systemctl", line 222, in enable
    config = SystemdFile(self.root, path, instance_unit_name)
  File "/build/lmp/build-lmp/tmp-lmp/work/intel_corei7_64-lmp-linux/lmp-factory-image/1.0-r0/recipe-sysroot-native/usr/bin/systemctl", line 31, in __init__
    self._parse(root, path)
  File "/build/lmp/build-lmp/tmp-lmp/work/intel_corei7_64-lmp-linux/lmp-factory-image/1.0-r0/recipe-sysroot-native/usr/bin/systemctl", line 80, in _parse
    k = m.group('key')
AttributeError: 'NoneType' object has no attribute 'group'

I hacked the systemctl python script to print out the path of the unit file and the currently examined line, and the exception occurs right at the first line containing "[Unit]".