On overly sensitive vacuum switch, no doubt. A filter has to get fairly dirty to turn on the light if all is working properly. I recently had a skidsteer that would turn on the light with a new filter if the engine was revved all the way up. Bad sensor. Have your dealer drop you one in the mail and you should be good to go.
Hopefully your dealer is better then mine and won't claim your address doesn't work. I have no use for dealers that lie to me. Unfortunately we only have two within 60 miles.