[achrysos]

Thanks - but my point is that each time that I uncheck the "Mark complete when completing last item", I will then return to that project and it will be set again. Not immediately - and this is what is really puzzling - but after an undetermined amount of time (days/weeks).

In my mind this is clearly a bug, but I just cannot see a common denominator in what I do that might trigger it, i.e. reset the checkbox.