Mastery Undefined, +0 Mastery Points and no Grade?

I'm having a lot of fun playing off-meta Ezreal support, I just won a ranked game where I did really well and I received no mastery points and no grade for playing the game. I really want to get Mastery 7 on Ezreal as supp, I got to Mastery 6 but I think the system changed, so I need S grades and now I can't get them

I think the system needs to detect your role to give mastery and if it can't detect your role it just gives you nothing, which really sucks for off-meta stuff.

Also Ezreal support is actually really good, fun too