LMS 8.0: Only scanning half the changed files?

This is happening with LMS 8.0, specifically this setup:


I don't remember it happening with versions before 8.0, but it may have.

When I rescan after changing lots of music file tags, the scanner discovers all the changed files but then scans only about half of them -- the progress bar moves incrementally over the first half of the set, then suddenly jumps to the end. If I repeat the scan after it completes, approximately half of the original number of changed files are discovered, and again only half of those are scanned.

This repeats, successively halving the number of discovered changes, until eventually only a small number (like 50) are found, and then those are completely scanned.

I can reproduce this at will:

1. Use foobar2000 to modify tags of 1000 files.
2. In Settings:Basic Settings:Rescan Media Files, configure for "Look for new and changed media files" and click Rescan.
3. In Settings:Information, watch as 1000 changed files are discovered and allegedly scanned.
4. When the scan completes, repeat from step 2 and notice that this time, around 500 changed files are discovered and scanned. Repeat again and see 250 changed files, etc.

In the screenshots below, you can see the progression in successive scans: from 1761 files, to 861, to 411, to 200, to 100. Only 5 images may be attached to a post, but the final two stages were 50 and 0.

Is this a known issue? If not, any idea why it might be happening on my system?

(Sorry for the image quality. I uploaded as GIF, but the images were automatically transformed to blurry JPG.)

Attached Images