According to Dave Meltzer, WWE is indeed moving forward with plans to turn Bayley heel. However, things aren't going quite as quickly as they planned, hence why she was replaced with Sonya Deville in that mixed tag team match with Elias against John Cena and Nikki Bella at a Madison Square Garden live event (Bayley competed in another match on the card as a babyface).
Why Bayley hasn't turned heel as quickly as planned isn't specified but it could have something to do with the fact WWE appears to be building to a WrestleMania match featuring her and Sasha Banks.
Bayley has, in fact, been making some heel moves on RAW as of late and while many fans have assumed that this is all misdirection for an eventual Banks heel turn, it would do her a lot of good right now. After all, bad booking has played a big role in Bayley not connecting with audiences as part of the main roster, so a heel version of her character could be just what's needed now.