Bug: Media Encoder not encoding audio on MP4 in version 24.5 update

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Issue - Media Encoder no longer encodes audio in the preset for Youtube 4K videos. Audio is checked in the project, but no sound comes out.

Adobe Media Encoder version number - 24.5

Operating system - Windows 11

Steps to reproduce - A media project that plays fine in the latest version of Premiere along with audio does not encode audio with the video in the final render. 

Expected result - Audio should be rendered with video

Actual result -  Video renders but no audio on output. No warnings shown during render.

FIX: Revert to Media Encoder v 24.4.1 Build 2 and same project encodes both audio and video fine.

Optional but useful: upload media and/or project files, screenshots or screen recordings that demonstrate the issue.  - No relevant screen shots as this fails silently (no pun intended), and project files are too big to share.

Also to note - this is the second bug I have 'obtained' following an upgrade. Does Adobe run test vectors that exercise all of the features on each upgrade, or is that an exercise that they prefer to leave to a user?