isn't that how it supposed to be? considering their last save is near the end of season 1 (and the whole apk only contains the start and end of season 2 so loading a save from season 1 won't do anything since it's literally separate now. ),
The game will continue to season 2 just like how i had no problem proceeding and finishing season 2 update by starting new game it will then load the data from the latest save file from s1 allowing you to continue or play season 2(i think). (Btw i love this game sm!, can't wait for liam or Rule B to wield his own knife!