am I storing my unused matcha right?

Guys. I have about 8 tins of Rocky’s matcha. I put them all in the freezer to store because I only like to actively use 1 tin opened at a time.

When I was ready to use my 100g tin, I took it out of the freezer and put it into the fridge for 24 hours (avoid humidity). Then I started using it daily. It tastes kind of off, so I’m wondering if I did something wrong.

Should I keep storing this tin in my fridge or keep it in my pantry? I only use 1 tin at a time, and drink matcha daily. TY!