They want act 2 to begin with a bang; you hit 5 when u get off of boat and have tons of shiny new skills and spells to play with since it is quite the leap for a lot of classes
This is perfectly fine and I fully expect them to drop xp gain down a little bit as you could definitely hit 5 without the cap which would trivialize whatever remaining content you have in Act 1 which just isn’t fun.
I’m more curious as to how they will handle solo characters since XP is the same with or without a full party but there are certain fights I don’t think will remotely be possible with everyone focusing strictly on you and your one pet/familiar.
I could be wrong tho and it’s next up on my play throughs.