The betting is bugged. A number of times, the AI players have raised themselves, or I have been offered the opportunity to raise myself within the same card. You can't do this.
For example, I'm 1-v-1 on another player, and a new card goes down. They raise. I call. They raise again, and I have to call AGAIN for the next card to go down.
In poker bidding, if you raise, and everyone else folds, calls, or goes all-in with an amount less than your raise, the turn is over, and you cannot raise again.