I think that this is at least somewhat normal behavior for french-door refrigerators. The left hand door on Whirlpool-built french door refrigerators has the pivoting "flap" that seals the space between the two doors. When you close the left-hand door, this flap has to fold under the right-side door. If you close the LH side quickly, the action of the flap inserting itself under/behind the RH door can be enough to pop the RH door open.

It MIGHT be that there is something about the folding flap on your unit that isn't aligned quite right, but it might also be perfectly normal. You might just have to train yourself to shut the LH door more slowly. Actually, with ours (a Jenn-Air unit that is basically the same as Whirlpool Gold, and KitchenAid), I've gotten into the habit of opening the RH side an inch or two as I close the LH side, and then closing the RH side on top of the flap.

Our refrigerators have a little "door ajar" alarm (as well as an indicator light) that starts making noise if the door is left open for more than a couple of minutes. But it isn't very loud....