Future Market's Lending Fee is taking 100g from me. Not 50g like it says it should.

I've played Future's Market for many games now since the last patch, and every time the lending fee should be charged, I get charged 100g, instead of the 50g I'm supposed to be charged. The rune in game even states that the fee is 50g. There's no mention at all of a Future's Market nerf, and I'm losing a lot of gold for this in my games.