Compaction corrupts imported EMLs in Local Folders

[roberts1000]

Thunderbird: 128.1.1esr (64-bit)
ImportExportTools NG: 14.1.2
No other plugins installed
Windows 10

I recently started exporting emails in .eml format from my provider, then importing them into Local Folders. The process appeared to work fine at first, but after a few days, I started noticing issues with the imported emails:

Symptoms/Issues

1. Many of the emails show (what looks to be) the source content, instead of, the correctly rendered email. It's particularly a problem with emails that have attachments. (Using Thunderbird's View > Message Body As > Original HTML has no affect. None of the options change how the email is rendered. Neither does the View > Display Attachments Inline toggle.
2. Some emails are completely blank.
3. Sometimes the same email will start blank, then show the source, after clicking away and coming back to the email.
4. Thunderbird would take much longer to open some emails - which is a sign that it's likely going to have one of the above issue. (This seems to have something to do with how much encoded content is present in the source, but that's just a hunch.)

I think I've traced this back to the compaction process that Thunderbird uses. I can't say for sure that ImportExportTools NG is involved, but the corrupted .eml's are only the ones I imported using ImportExportTools NG.

To Reproduce the Error

1. Setup Thunderbird as a fresh install.
2. Add an account for an email address you can use to test.
3. Install ImportExportTools NG.
4. Find any large image, that's greater than 1MB in size. (It will be used to trigger the compaction process so larger is better).
5. Go to Thunderbird's Settings > General > Network & Disk Space > Disk Space option. In Compact all folders when it will save over x MB in total, set x to 1MB.
6. Now, login directly to the email provider you added and send yourself an email, with the image as an attachment.
7. When the email arrives, export it as a .eml file from their website.
8. Go back to Thunderbird and import the .eml ile using ImportExportTools NG.
9. Select the newly imported email and Detach the attached image. (The Delete option also causes the problem.)
10. Close Thunderbird, then open it back up. The dialog should open, asking if you want to Compact. Select Yes to compact.
11. Now, navigate to the email in Thunderbird and view it. It should be corrupted. If it's not, close Thunderbird, open it and go back to the email. It's likely corrupted.

Other considerations

1. All of the emails that I've transferred to local folders, from online folders, using Thunderbird's Move to menu option look correct. They don't get corrupted when I compact, detach/delete attachments. To give this a shot, simply email yourself the same image file again if needed, then use Move to to move the file to a local folder. Detach the attachment, close Thunderbird, open it back up, compact, view the email ...
2. I tried this process with email addresses from two major providers. Both get corrupted so it doesn't seem to an issue related to original .eml that's generated.
3. Many of the emails I imported using ImportExportTools NG open correctly, at the moment, but I suspect Thunderbird hasn't tried to alter/compact them yet so they may yet get corrupted in the future.
4. If I try to use the Repair button on emails that are corrupted, Thunderbird simply deletes them and they're lost forever.
5. This issue isn't specific to images. I've seen it happen with Excel and PDF attachments as well.