In previous version of the website own it button it was easier to "guess" the state of the button. Currently "inactive" state of the button (or all buttons for that matter) is grey that stands out and active one is in the colour of background (suggesting is not active? or is it me) with the tick being darker.
For me at least this design choice is utterly confusing. Maybe make inactive buttons in the colour of background altogether or add colouring (actual colour like green?) to the website?