We've had no-loan days, missing loan days, broken limit orders, bets on resolved markets, and more. Then there's the weird profit spikes, but at least those don't seem to affect anyone's Mana balance or profit, just the display. And there are markets about them and when they'll be fixed or not:

/chrisjbillington/will-there-be-another-double-loan-d

/Joshua/how-many-more-no-loan-days-will-the

/Ernie/will-manifold-fix-the-random-profit-378c301eabab

Will there be a mana-affecting bug that wasn't anticipated or reported before this market was created, before February?

This is going to be a bit vibes based; I won't trade. If it causes a market to resolve, or contributes to a count, it's clearly anticipated. This market is about the Rumsfeldian uncertainties.