I had a plant while ago that first made 3 or 4 sets of regular 2 leafs and then started making ones with 3 leafs/branches, which is where i topped it and strarted training it for 3 main branches that splits to mane many more. However the pant ended up going hermie, which is a real shame because the plant was really really good in every way, tons of vigour and i had vegged it for over 2 months :/
Anyways im no pro with these but i did quite a bit of research when i found this plant.
First it seems that herming is quite common with these. I suspect its because it tries to grow more branches than normal and then has lower amounts of female flowering hormone than normal or something, not sure, but hermies are more common. Not all hermie tho.
From what i read, usually it starts to make normal 2 leaf pattern after it make two or few 3 leaf patterns. So i guess what you are dealing with 3 turning to 4 is even more rare. Maybe your will also start to do normal 2 leaf pattern at some point, who knows. I think its rare if that does not happen.
Good luck with it, would be nice to see some pics after its more developed to see how it went.