Someone on another thread stated this is caused by wind from a certain direction. That was my first reaction as the first time it was very windy.
Then I say that is a bad design, if we have to manually reset it after a gust of wind. Wind was my first thought as the first time it happened, it was indeed very windy. Since where I am from, the wind is almost always from the west. I could see that perhaps wind from an unusual direction could cause this and that is why no problem for the past 4 weeks.
I guess this means we will never be able to go on vacation again!