As in, fixed fixed? I'm also missing about 20-25 blocks worth of awards, showing as 'None.' Is that a display bug or a consequence of negative payout not yet paid back in? My missing awards start with block 989, same as the OP.
If the second, how long would we be mining for "free" until the pool breaks even?
If you're seeing blocks showing as None, you weren't mining. This entire situation did not have a single share submission lost. Nobody is mining for free. If you were donating 2.5%+ when the 24 NOT REAL BLOCKS were showing up in the list, and requested a payout, your confirmed rewards on My Account are negative, but you will still see normal block rewards in the list which show that you're paying back the amounts that you should have never received in the first place.