I figured out that my browser stay logged in the Lightning Node app/page when opening from local IP. This mean if someone access my PC (very unlikely but still) the seed backup is accessible by one click! Just to confirm I restarted the PC and the main Umbrel dashboard is logged out and not accessible, like other app (Thunderhub for example).
The worst is that I have no way to force to log out, maybe by removing a cookie but that really not convenient.
Did I do something wrong? Is it a known bug?