This appears to be a legitimate issue that could cause major ones for people who aren't aware of how the problem is working.  hui noticed it with his bets as well and brought it up in chat, and I realized the same issue was happening to me yesterday.

Laid out theoretically here..

Say I deposit .1 BTC and the first roll I do is .05 BTC and nothing happens in the window.  No confirmed bet, no balance change, nothing; so I assume the roll didn't go through.  Hit the roll button a second time and the same thing happens.  Balance still shows .1 BTC.  Hit the roll button a third time and now it tells me "Insufficient Balance."  Refresh the window, and sure enough the bets DID go through as loses, it just didn't show me what properly happened because of a bad gateway.

Understand what's happening here?  Not quite another nonce-gate, but if we're clicking the "BET" button and nothing shows up as going through, NOTHING damn well better go through or else our planned bets on a win or loss are out the window.

A retroactive fix then, for anybody else this happens to.  If you roll the dice and nothing shows as happening, refresh your window to be sure the bet didn't actually go through like you'd intended.

Hoping the current downtime is fixing the issue.