Browser source SpeechSynthesis audio is not recorded when "Control audio via OBS" is selected

Operating System Info

Windows 10

Other OS

No response

OBS Studio Version

29.0.2

OBS Studio Version (Other)

No response

OBS Studio Log URL

https://obsproject.com/logs/OXxpPl8wZ7n4t9ts

OBS Studio Crash Log URL

No response

Expected Behavior

SpeechSynthesis done inside a browser when set to "Control Audio via OBS" should be recorded on it's own audio channel in OBS, as well as be monitored if the monitor setting is enabled in Advanced Audio

Current Behavior

OBS should be able to both record and monitor the speechsynthesis audio generated by a browser source when "Control Audio via OBS" is enabled, instead it simply records nothing.

The browser source is capable of generating speechsynthesis audio when the option is off, that however goes through Desktop Audio/Default Output and is not ideal for my recording setup.

Steps to Reproduce

1. Add a new browser source pointing to Mozilla SpeechSynthesis demo page (https://mdn.github.io/dom-examples/web-speech-api/speak-easy-synthesis/)
2. Set the source property "Control Audio via OBS" to true
3. In Advanced Audio properties for the browser sauce, set Audio Monitoring to Monitor Only/Monitor and Output
4. Using the Interact tool with the browser sauce, type in some text and click Play.

Anything else we should know?

Thank you whoever made the Analyzer of OBS log files. It's most likely unrelated to this issue but I can see now some other performance settings in OBS I was never aware of.

Start by reproducing the issue with the MDN SpeechSynthesis demo in an OBS browser source on Windows 10 and OBS Studio 29.0.2. Compare “Control Audio via OBS” enabled versus disabled, including the Advanced Audio monitoring modes, and inspect the provided OBS log. Done means SpeechSynthesis audio is recorded on its own channel and monitored when enabled.