Boing Boing feed resets itself every so often

Every couple of weeks or so the Boing Boing feed on my account resets itself and goes back about a month or so, marking all the items unread. This means I have to go through about 150 items manually, or mark them unread and miss the last day’s worth.

Any idea what is causing this or how to fix it? All my other feeds behave normally… :-S