Sync creates an RSS mess

I have a folder of RSS feeds in my Safari bookmarks bar. I started syncing with foxmarks to firefox at work about a day ago. When I got home from work the first day firefox was synced, my RSS feeds mostly did not work. For starters I noticed that they had not updated by themselves. I then found that many were no longer valid feeds, and upon closer inspection realized that somehow the URLs had been slightly modified.

I manually replaced each one with a new working bookmark, which foxmarks busily updated after each one. Everything looked good last night after I was finished. Today I'm here with Firefox (and screen sharing back home to see what's going on with Safari), and I have a big mess. Lot's of duplicates, many have been altered again for some reason.

I fixed them again, in Firefox this time, and as soon as the syncs completed it was back to the mess again.

I'm wondering if this has something to do with the way RSS is handled in Safari vs. Firefox.

Any thoughts?

Here are a couple screenshots:
Before:
http://dl.getdropbox.com/u/12286/safa...
After:
http://dl.getdropbox.com/u/12286/safa...