To troubleshoot and see if this is indeed the issue, you can check all mDNS records on your network using zeroconfServiceBrowser | Tobias Erichsen (tobias-erichsen.de).
I would run it when everything works as expected (you should see an entry for your P1 dongle) and save a screenshot of it and then run it again when it fails and compare.
If this is indeed the issue, then depending on your network device, configuration and troubleshooting will be different. Sometimes, mDNS is also overloaded if you have too many devices using it. You can get more info here on a potential solution: Issue with Google Chromecast
A short update:
Since I stopped 3 days ago the flows that restarted the Homewizard app every morning, the sockets and P1 didn’t go offline anymore. So far… so good. Stays strange for me that after a restart from the app, the sockets won’t come online. But for now I keep checking the next days.
I understand your view, I did see some of my sockets are slow in mDNS updates.
Not sure if you have some local/internal dns server like pihole or adguard running for adblocking. I use adguard for example to protect my kids for nasty stuff and some caching dns results does help. mDNS is *.local so if you have for example something resolving locally it is advised to step away from that and use something else than .local like *.lan for your private devices.
