First thing, make sure your camera has the latest firmware update. Go to Moultries web page. You can find "how to's" there. Probably won't help but it never hurts for the camera to be up to date...
The M-50i cameras have a nearly 2 second video trigger. They also have a 43° detection angle but a 36.7° F.O.V. Which means the target should be in the detection zone when the camera can finally "see it"...Try setting your camera at angles so your camera has more time to "wake up".