Ancajas seems doesn't have a medical condition but just struggling to reach the required weight as maybe he is really getting bulky and bigger for his current division. That's why a good nutritionist is necessary and they hired a new one as part of the team that will condition Ancajas until the day of the fight.
I think he has nutritionist in his side if I'm not mistaken, but there could be some lapses, maybe in the training or after the weigh in because it wasn't enough for Ancajas to fully restore his body to prime in his fight night. And usually if a boxer gets cramp along the fight, it means he lacks fluid and this might be the case for Jerwin and that's why his performance was lacking, as if it was a different version of him that we are watching. But in can be corrected though, and that is the good thing for him, make the weight and then recover and replenish his body and be 100% against Martinez. Get his belt back, and if in the next fight, he can't make that weight anymore, go to the next and have another goal of winning a belt for his Filipino fans.