it’s not the browser freezing over, it’s just the Main UI loses the connection to openHAB API. Sometime (not always) there’s a corresponding entry in the logs.
but perhaps we should split this thread and create a new topic for that behaviour? Some admin, please 
?
edit:
I tried to replicate this right now.
first, the described behaviour sets in (I can’t see the lists anymore in the MainUI, but still can navigate aka lost connection)
after a while (not immediately) the following entries show up in the logs. I had five tabs open in one browser and two in another and both went unresponsive at different times. So these entries are more than tabs (perhaps requests?), and all at once:
2025-09-25 10:40:57.868 [WARN ] [openhab.core.io.rest.auth.AuthFilter] - Unauthorized API request from 192.168.78.230: Error while processing JWT token
2025-09-25 10:40:57.873 [WARN ] [openhab.core.io.rest.auth.AuthFilter] - Unauthorized API request from 192.168.78.230: Error while processing JWT token
2025-09-25 10:40:57.876 [WARN ] [openhab.core.io.rest.auth.AuthFilter] - Unauthorized API request from 192.168.78.230: Error while processing JWT token
2025-09-25 10:40:57.878 [WARN ] [openhab.core.io.rest.auth.AuthFilter] - Unauthorized API request from 192.168.78.230: Error while processing JWT token
2025-09-25 10:40:57.882 [WARN ] [openhab.core.io.rest.auth.AuthFilter] - Unauthorized API request from 192.168.78.230: Error while processing JWT token
2025-09-25 10:40:57.885 [WARN ] [openhab.core.io.rest.auth.AuthFilter] - Unauthorized API request from 192.168.78.230: Error while processing JWT token
2025-09-25 10:40:57.887 [WARN ] [openhab.core.io.rest.auth.AuthFilter] - Unauthorized API request from 192.168.78.230: Error while processing JWT token
2025-09-25 10:40:57.889 [WARN ] [openhab.core.io.rest.auth.AuthFilter] - Unauthorized API request from 192.168.78.230: Error while processing JWT token
2025-09-25 10:40:57.892 [WARN ] [openhab.core.io.rest.auth.AuthFilter] - Unauthorized API request from 192.168.78.230: Error while processing JWT token
2025-09-25 10:40:57.894 [WARN ] [openhab.core.io.rest.auth.AuthFilter] - Unauthorized API request from 192.168.78.230: Error while processing JWT token
2025-09-25 10:40:57.897 [WARN ] [openhab.core.io.rest.auth.AuthFilter] - Unauthorized API request from 192.168.78.230: Error while processing JWT token
2025-09-25 10:40:57.900 [WARN ] [openhab.core.io.rest.auth.AuthFilter] - Unauthorized API request from 192.168.78.230: Error while processing JWT token