When using Portable Preview in domain environment, opening a terminal as a different user when current user has terminal window already open results in second terminal for current user and not the different user

[PGomersall]

Windows Terminal version

1.23.10353.0 and 1.23.10732.0

Windows build number

10.0.26100.3476 W11 24H2
Windows Server 2025

Other Software

N\A

Steps to reproduce

Computer needs to be domain joined. Also fixes noted at the end of #18105 needs to be applied - i.e. Accent colors.
Setup WT portable Preview in location accessible to all users, e.g. C:\WT
Add .portable file and settings.json in settings folder.
Run C:\WT\WindowsTerminal.exe as current user
Terminal open correctly as current user
Run C:\WT\WindowsTerminal.exe as different user
Terminal requests correctly different user's credentials
Terminal then opens as current user and not the different user.
This has been tested on different computers and OS's all at least 24H2 Windows 11 or Server 2025 and all exhibit same effect.
Have used standard users, admin users, domain admin account with and without smartcards.

Notes:
Using Terminal portable stable (not preview) works correctly.
Using Terminal Portable stable for one session and Preview for the other works. Same is true for built-in app version and Terminal portable preview.
This does not seem to occur on a non-domain joined computer

Expected Behavior

Opening Terminal as different user when one from current is also running results in second terminal opening as the different user and NOT the current user.

Actual Behavior

Terminal Preview opens as same user as that running the first Terminal session.

[lhecker]

When discussing this we had the theory that HWNDs are global objects, so when we call FindWindow it gets us the wrong window. An idea to fix this may to add the SID to the HWND name. We use a NT mutex object to prevent two instances from being concurrently created and we could also swap that one out for one that stores the HWND in a shared memory section.