[BUG]: Possible Elektron Overbridge interference with Montage M in MIDI 1.0 mode with Yamaha Steinberg driver

Reported on Discord.
https://discord.com/channels/980245825202552942/1480003241877176535

Put Montage M in MIDI 1.0 vendor driver Mode
Use the Yamaha/Steinberg vendor driver for the Montage M

From the customer report:

Issue Summary: MIDI ID Corruption (Feb/Mar 2026)
I suspect a recent Windows 11 update has caused a critical conflict between Elektron Overbridge and the Yamaha Montage M (Steinberg Driver). If Overbridge is active and the Montage is power-cycled, Montage MIDI breaks permanently until a full driver reinstall/restart.

The Verified Fix (Must be repeated if it breaks)
To resolve this, you must force Windows to rebuild the device node during active communication:

Power on and connect the Montage M.
Uninstall the Steinberg driver while the unit is on to trigger Windows to tear down the corrupted node.
Immediately reinstall the driver and RESTART PC.
This allows a "live handshake" that registers composite MIDI/audio endpoints before the Overbridge filter interferes. This remains stable only as long as the Montage stays powered on before launching your DAW. Turning off the Montage while Overbridge/Elektron gear is active will break it again.

Technical Evidence: Registry & MIDISRV Inspection
Comparison of the Windows MIDI Services (MIDISRV) states:

Working State (MIDISRV ID): MIDIU_KSA_12562777948002158499

Result: "MONTAGE M-1" through "M-4" friendly names appear on all ports.

Broken State (MIDISRV ID): MIDIU_KSA_11462550940207746801

Result: No friendly names; Bitwig sees anonymous/unnamed ports. Montage slots appear empty or are overridden by the Syntakt.

The Bug
When the Montage reconnects during an Overbridge session, MIDISRV generates a new KSA identifier instead of recognizing the existing one. Overbridge is interfering with MIDISRV's device identity resolution, preventing the Montage from matching to its registered friendly names and port assignments. This is a specific, actionable bug for both Elektron and Microsoft.

This needs investigation because as helpful and detailed as the report is, the technical analysis/conclusion does not seem correct (most of it omitted here due to confusion around if MIDI 2.0 discovery was involved).

However, the fact that a new SWD is generated when the Montage is powered back on is unexpected and troubling, as the Montage was not moved to a different USB port, driver was not changed, etc. It should also have a unique serial number even in MIDI 1.0 mode, so our SWD should be the same.

Need to test both Overbridge and the Montage (in vendor mode) together under Windows MIDI Services. It's also possible this is simply the dynamic ports bug and/or surprise removal in some way, due to how Overbridge communicates with devices. That still doesn't explain the SWD change, however.

Needs investigation.