Update: I had the issue with the homescreen again after i rebooted my synology. I’m running grafana in a docker and after the restart it didn’t start the grafana docker. In pimatic i created a iframe device wich opens the grafana interface, but after the reboot it couldn’t open the url.
I think the homescreen issue is related to the iframe plugin. If the iframe can’t open the url the issue with homescreen occurs. After i deleted the iframe device that opens grafana i could use the homescreen link again.