It's conceivable the announcer is creating more than the max spl of the 412. (Shure says: Cardioid: 124.2 dB, Supercardioid: 122.7 dB, Omnidirectional:116.7 dB). And it is easily possible that the announcer is overloading the capsule with wind energy. If the capsule is getting held at an extreme position by wind it could be in the red and sound like it's "cutting out".
In my experience the 412 looks pretty good, slim and trim. But, you need to have the wind source at least a foot away, and preferably more to avoid disaster. With a close talking announcer, the standard windscreen is not up to the task.
You may be able to rig a real (studio/radio style) pop filter to a 412, but it'll probably be easier with a more stable stand, or you may find that something as basic as a 58 with a fat foam screen will do the job nicely (The 58 begins distorting around 150db of 100hz)