Firefox keeps forgetting the favicons in my bookmarks

As the title says, Firefox keeps forgetting the favicons in my bookmarks, and it's driving me nuts. Why does this happen?

I just got through refreshing all my favicons yesterday by visiting all my bookmarks again, and all the favicons were generated and appearing in my bookmarks.

Now today, half of them are missing again. They're just the generic icon. Some are still there, but half or more are gone. So what's happening to cause this? Is it a memory issue? How does Firefox store it's favicons?

Here is one related link from mozillaZine; if that does not help, go to the forum and do a search:

Missing Favicons mozillaZine Forums

Well I just deleted my favicons file and revisited all my bookmarks again.

But I have a new question about favicons now. Most sites generated the favicons fine in my bookmarks in Firefox. However, a few won't update so I just have the generic icon. If I open the same exact page up in Chrome, it generates a favicon. Some favicons just don't seem to appear in Firefox. Any idea why?

Also, I exported my Firefox bookmarks in html format. I then imported them into Chrome using that html file. I read the html file will contain all the favicons. However, when I imported that file into Chrome, a good half or more of the favicons were not in the imported bookmarks and I had to revisit the sites in Chrome to generate them.

Is that Firefox's fault for not properly exporting the favicons in the html bookmark file, or Chrome's fault for not importing them correctly?

And once again, Firefox just lost half my favicons in my bookmarks. They were fine yesterday.

Why is this happening??

I previously deleted the favicons file and revisited all my bookmarks to regenerate them. Now it forgot half of them all over again.