PiHole: VIRTUAL_HOST argument ignored


I’ve installed PiHole with Balena as my first project to try out Balena. Works great!
The only thing I’m unable to set is the docker argument VIRTUAL_HOST. Setting it as a Device Service Variables works, but is ignored when starting the service. Is this a limitation of how balena works on a network level? In PiHole the VIRTUAL_HOST is automatically set to the UUID of the device.