I think it's because Ancajas is more careful now, he is not so aggressive, he fight smartly to be able to comeback being a champion. Personally, I believe that he will win, but this fight is more like very technical as both wants to win. As per record, Ancajas is more experience with 34 fights while
Takuma Inoue only has 18 fights, and also Inoue's KO rate is very low as he only have 4 KO wins from 18 fights, which is very opposite to his brother, so no doubt Ancajas will get this win.
Inoue will have a big problem if Ancajas shows no respect for his punches, This is what exactly happened in his last fight against Wilner Soto, he chased Soto all throughout the fight because his punches had no effect on Ancajas, Inoue has a very low knock out rate and he'll have to be more technical and he has to show stamina because Ancajas will chase him.
Ancajas should dominate or knock out Inoue for him to win the title because this is Inoue's hometown and if the fight is close they will favor Inoue, I don't see Ancajas losing this fight he needs to win the fight it's hard for him to get a shot in the world title because he had 2 losses in a row in a world title fight.