P: Stack overrun issue

Even cutting clips, cropping a clip and enable/disable gives the error message

Premiere recently developed a specific problem: Whenever I attempt to export my main sequence, Media Encoder opens, and gets as far as displaying text in the Output Preview, but the blue progress indicators never come on, and the encoding never begins. This happens regardless of whether I try to export the whole timeline or just one small section.

Perhaps not coincidentally, I have noticed that in the course of troubleshooting, when I cut or paste certain sections of clips,  red warning boxes appear with the message: "onTrackItemAdded: Stack Overrun" or "onTrackItemRemoved: Stack Overrun".

If I delete all audio from the timeline, the video exports fine. But not vice-versa. I have also determined via cutting/pasting that the first 35 minutes of the whole timeline is okay, but after that it causes problems.

This does not happen with other large Premiere projects. Nor does it happen with other timelines containing other (non-cut-and-pasted) source clips. I am able to create a new project and import the same source files, and export with no problems. In the recent past I have routinely rendered and exported very large files (including RED 6K), so I am fairly certain that this is not related to my system.

I suspect that most of my audio clips are corrupted somehow, and that I probably need to rebuild most of my audio. (Also, this project is a documentary that was built by someone else from a wide variety of sources, and it may be possible that there are varying audio sample rates.) But this is a 2-hour feature, so if there is another less tedious option, I'd love to hear it first.

Any help is appreciated!

Here is what I have attempted so far, to no avail:

- Multiple software and system restarts

- Updated Premiere Pro and Media Encoder

- Updated Nvidia GPU studio driver

- Cutting and pasting into a new timeline

- Importing the timeline into a new project

- Set Source Range to Sequence In/Out vs. Entire Sequence

- Deleted Media Cache, Peak Files, and Scratch Disk render files, and regenerated all

- Disabled CUDA GPU Acceleration in General Setttings

- Disabled CUDA GPU Acceleration in Media Encoder Renderer

- Attempted export in a different format (Quicktime ProRes 422, instead of H.264)

- Trashed Preferences

- Confirmed plenty of available disk space

- Disabled H.264/HVEC hardware accelerated encoding and decoding

- Optimized rendering for Memory

SPECS:

Premiere Pro 2021 version 15.4.1 (Build 6)

Media Encoder 2021 verson 15.4.1 (Build 5)

Windows 10 Home Version 10.0.19042 (Build 19042)
CPU: Intel Core i9-9900 @ 3.60GHz
GPU: Nvidia RTX Quadro 4000

Memory: 64GB