...EVERY time a cursor goes to the top when in full screen mode?

'Cause it's annoying as heck.

It's their marketing scheme. 

When they have 5000 points (not counting actual units killed) to "win" 5 zapphires and 5 Necromancers as the lowest bar for spoils, they want to sell you tons of units to lose to "win" these "covetted" units.

They are not interested in giving us an enjoying player experience. They are only interested in selling things that are completely unecessary. 

And now, they pretend to not know what you are talking about to stall any productive conversation. 

And when you point this out to them, they ignore you.