a center can't be called for a false start by the rule. somehow i got false start because of my center and i've seen more centers getting false start.
is it legal by the game?

This is completely false, a center can absolutely be called for a false start in real football.

And it's not just your center who is getting the false starts, other players are getting called but the blue circle around the center is what shows. You can see who jumped in the play by play box located right below the field screen or on the field screen if you use the overlay.

This. As a former center this is entirely possible. And can happen much easier than you'd think