Mismatch in filling of the circles? :)

I'm running a telegram countdown channel and I noticed that the circles don't fill up equally! Which doesn't make sense? One counts down from 100%, the other counts up to 100%. Both numbers equal 100%, always. Yet one will get 1 circle half filled, while the other remains at a quarter for quite a bit longer... Why?

Example: https://t.me/Trump_Countdown/100