Starting Windows magnifier changes ducking from "always duck" to "duck when outputting speech and sounds"

[Qchristensen]

Steps to reproduce:

1. Set NVDA's audio ducking option to "Always duck".
2. Set some music / audio playing on the PC
3. Press WINDOWS+PLUS to start Windows Magnifier

Actual behavior:

At step 3, the playing audio gets louder (as it is no longer being ducked). NVDA behaves as if the setting is now set to "duck while outputting speech and sounds".
Opening the audio settings, the option still appears to be set to "always duck". Changing the option to something else, applying, then changing it back to always duck works until Magnifier is restarted.

If Magnifier is started before NVDA, the existing setting (ie always duck) is respected.

This was reported by several people in the NVDA user group: https://nvda.groups.io/g/nvda/message/123535

I can replicate with eSpeak-ng, and Windows OneCore (and one user reported it also happens with Eloquence).

Expected behavior:

Audio ducking should work unchanged when magnifier starts.

NVDA logs, crash dumps and other attachments:

Nothing is recorded in the log, even at debug level, when Magnifier is started - aside from the keystroke to start it.

System configuration

NVDA installed/portable/running from source:

NVDA version:

NVDA 2024.4.2

Windows version:

Windows 11 (64-bit) Version: 24H2, Build: 26100.3194

Name and version of other software in use when reproducing the issue:

Other information about your system:

Other questions

Does the issue still occur after restarting your computer?

Yes

Have you tried any other versions of NVDA? If so, please report their behaviors.

If NVDA add-ons are disabled, is your problem still occurring?

Yes

Does the issue still occur after you run the COM Registration Fixing Tool in NVDA's tools menu?

Yes

[gexgd0419]

Starting Windows Narrator also cancels NVDA's audio ducking, even when audio ducking for Narrator is turned off.

I guess that like Narrator, Magnifier also changes the system-level audio ducking setting, which overrides NVDA's audio ducking. And Magnifier does have a feature to read text on screen, which makes audio duck while reading, so I guess that it makes sense for Magnifier to touch this setting. The problem here is that Magnifier changes the setting on start.