Did Tyrion make a deal with Cersei and will betray Daenerys?
Many fans believe that an important conversation went down between Tyrion and Cersei that wasn't shown in the Season Seven finale. Remember when Tyrion was convincing Cersei to work with Jon/Danenerys and noticed that she was pregnant, then the next scene cut to them back in the Dragonpit? During that gap, Tyrion might have made a deal with Cersei to ensure that her unborn child would be the king/queen to succeed Daenerys, who Tyrion believes is unable to have children. That would explain his concern while listening to Jon and Dany have sex on their steamy romance cruise in the finale. If she has a baby that would really mess up his plans.
Prediction is suggested by Tatevik from the House Stark of Winterfell
Winter is coming