There is no drop rate increase.
If you can read this properly, Sarah clearly says that “portals (gold and item) have always given you lots of free gold, tokens, as well as higher drop rates of legendaries”
For you illiterate people who rushed past this and just assumed, let me clear it out:
Portals have always had higher drop rates than other missions. Nothing about INCREASING the drop rate was mentioned.
I also see many people complain about the drop rates being absolute trash. But honestly, it depends on each player. Complaining won’t do anything.
You may get 1 legendary per 5 refills while another player may get 3 legs in 1 refill.
It just… varies between players. Your next portal might be an absolute legendary mine or not.