Bowls have a natural "settle level" that the water will drop to. It can't be changed. Sometimes, the toilet's fill valve will divert a little too much water to refill, so that the bowl slightly-overfills before the water shuts off. This can happen if, for example, you set the toilet to turn off a little higher in the tank than the manufacturer planned, or if it was set a little high overall at the factory. In any event, it's normal-ish.
The optimal water-saving toilets try to get the bowl to fill just exactly to the "settle level" when the tank is full and the refill of the tank and bowl turn off. I can explain more if this doesn't make sense.
Meanwhile, when you look at a toilet cutaway, you can see why the natural settle level exists: put more water in the bowl than designed, and it just flows slowly over the weir. Put a lot in at once, and the trapway fills up, creates a siphon, and causes a flush, sucking out the entire contents of the bowl, which is then refilled as the tank refills. This happens because a percentage of the water flowing through the fill valve is diverted from filling the tank to go through that little refill hose and down the overflow tube into the bowl for refilling.