Critical Export Issues on 27.0 BETA

I can confirm that I'm having the same problem.

In the latest version, 27.0.0 build 32, this no longer happens when exporting from Premiere, but it still happens when exporting from the encoder.

I'm also having this other problem

Summary: Final program export loses one audio channel (stereo collapses to mono/single-channel) in Premiere Pro Beta, regardless of export format.

Description: When exporting the sequence "Final multicam" directly from the Timeline, the resulting video file only contains audio in one channel. This happens consistently across multiple export formats (tested with H.264/MP4 and MOV/QuickTime), ruling out a codec- or preset-specific cause.

Verified NOT the cause:

• Sequence audio track (Audio 1, 4 clips) was inspected: Volume levels are correct and identical across all clips, no clips are muted.
• Channel Volume (source-to-stereo mixdown) parameters show identical Left/Right values on every clip — the panning/mix is symmetric and correct.
• Exporting the audio alone as a separate WAV file produces correct, fully stereo audio.

Conclusion: The sequence and its audio mix are correct. The channel loss occurs specifically during video export/rendering (audio muxed into the video container), not in the timeline or source media.

Environment: Premiere Pro (Beta build)

Steps to reproduce:

1. Open sequence with stereo audio mix confirmed correct (verified via standalone WAV export).
2. Export to video (tested: H.264/MP4, MOV) using "Match Source" or other presets.
3. Play back exported file — audio present in only one channel.
4. Change export format — same result persists.

Expected result: Exported video retains full stereo audio matching the standalone WAV export. Actual result: Exported video audio collapses to a single channel.