On both mythical and regular item Vault it shows that I do not have ny items in my inventory (for ex: I have Gmode but it didn't put a check or even highlight it) This lowers my chance for those gold boxes and myth boxes to recieve "(insert percentage) not in inventory) as well as when there was the labor day sale I unboxes a red rain when the game clearly took it out.

Sorry to hear that

Not entirely sure how the mythical boxes calculate this but i'll ask.

Have you tried clearing your cache and checking if it shows up properly again?

no but I shall try.
EDIT: I have tried it doesn't work still no "check" marks on the item vault (I am using chrome/firefox)

Hello,

I've asked around a bit. It's a visual bug that will be fixed later - it does *not* affect your chances.

Thank you