The issues with Windows 11 MIDI have now been resolved by Microsoft since end of April 2026 - Windows 11 Update - version 25H2 OS BUILD 26200.8328 and above.
The recent Windows MIDI Services update (Windows 11 retail 24h2 and 25h2) causes SSL V-MIDI Ports to disappear and therefore UF8 and UF1 to stop working, as the MIDI controller ports are unavailable in the DAW.
This Microsoft Article covers the issue in more detail and provides some suggested workarounds - https://devblogs.microsoft.com/windows-music-dev/windows-midi-services-rollout-known-issues-and-workarounds/
Users have also reported to us that uninstalling the latest Windows Update fixes the issue.
The linked Microsoft article above states that Microsoft are planning a bug fix for this issue - expected at the end of April