Advanced motion detection cuts video length too short

HiI've noticed that if the advanced motion detection is on that the video recording length on my solar battery camera reduces to only 6 seconds. This isn't anywhere near long enough to be useable. If i switch off the advanced motion detection i get longer recordings, but i am then unable to set the correct zones and therefore i get lots of notifications that i otherwise wouldn't have received.Is there a bug or a reason that i cannot set advanced motion detection zones and have video recording at 30 seconds or more?ThanksStew