UserAgent: Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36

Steps to reproduce the problem:
For some reason, "expired" auction pages on eBay (as of June 2016) are able to reliably reproduce the issue.

I am running on Windows 8.1 Pro x64.

1. Install the "Save as MHTML" extension (I also have it enabled in Incognito mode, if that's relevant).
2. Go to eBay.com and open an expired auction:
2.1. Search for "GeForce 980 Ti" or some other often-sold item
2.2. In the search results page, in the filter list to the side, scroll down to "Show only"
2.3. Click "Show only" > "See all"
2.4. In the popup, check the "Sold listings" checkbox (this will make eBay show expired and sold listings in normal search results)
2.5. In the search results, click an item that was sold
2.6. The auction page should have a yellow bar saying "This listing has ended".
2.7. Click on the item image (with the "Sold" banner in the bottom-right corner) to go to the Expired Auction page.
2.8. You should now be on the Expired Auction page - it is different to the page in steps 2.6 and 2.7 because it has the auction's original image gallery displayed.
3. Click the "Save As MHTML" extension button and click "Save as MHTML > Single Page"
3.1. The extension simply calls "chrome.pageCapture.saveAsMHTML" to save the page.
4. You will get a File Save dialog with a GUID as the filename.
5. After clicking Save, you'll see the file wasn't created.
6. I got the Chrome Downloads window open and in the history (after the GUID) it says "Failed - No file".
7. I don't get any console error message output in either the page's console or the extension's background page console.

What is the expected behavior?
Chrome should:
1. Respect the original filename
2. Actually save the file

What went wrong?
Chrome prompted to save a GUID and never saved anything.

WebStore page: https://chrome.google.com/webstore/detail/save-as-mhtml/eomfifclcdpkaghkehajpolkdnkmegfa

Did this work before? N/A 

Chrome version: 51.0.2704.103  Channel: stable
OS Version: 6.3
Flash Version: Shockwave Flash 22.0 r0

Other pages seem fine, such as eBay's homepage and active (non-expired) auction pages. There must be something about eBay's expired auction pages that makes it fail.