I assume you're comparing the current season to S2, because that's the only season where his OBP is lower than the current season.
First, he's only pitched 16 innings, so it's a small sample size. He's also had 2 HBP, which would not be reflected in his WHIP but would be reflected in his OBP allowed. And 2 HBP in 16 IP's has a lot more impact to his OBP allowed than the 8 HBP in the 188.2 IP's he had in S2 did.