Flush handlers does not support when conditional

[pcm32]

I'm using this role to do everything but deal with the service, which I deal with separately with supervisor - long story, not on privilege escalation allowed scenarios. When setting a value for gie_proxy_setup_service different to systemd to skip that part, I guess the following error:

TASK [usegalaxy_eu.gie_proxy : Install Systemd service unit] ******************************************************
skipping: [uk2as006]
[WARNING]: flush_handlers task does not support when conditional

RUNNING HANDLER [usegalaxy_eu.gie_proxy : Restart GIE Proxy] ******************************************************
fatal: [uk2as006]: FAILED! => {"changed": false, "msg": "Could not find the requested service galaxy-gie-proxy: host"}

Any chance of using something different than flush handlers or maybe add the when on the handlers as well?

Thanks!