I use Antivir Pro and even when I disable AV Scan in Task bar it doesn’t work. Antivir has a special Web Protection functionality what is still active even when AV scan is disabled. I have to configure this web protection to exclude the Ip Subnet or DNS Domain of my Home Network or to exclude the Mime Type from scanning.
you can configure it at Security => Security Options => Web Protection => Settings
Then everything is working again.
I get all values, switch and badges are working.
I was totally confused, because the demo website of openhab was working like a charm but with the same browser on the same machine I got problem with my own openhab server.
Maybe there is in sophos a web protection too?
After the configuration change of my AV the Events (Sse) are recognized and processed correctly.
I ‘played’ with OH3 today and didn’t have any problems anymore
Maybe your AV has add-ons/extensions to your browser (Chrome and Safari). Maybe in Firefox not enabled and so its working