doors and stairs dissapearing

i saw the door issue of doors dissapearing on relog was resolved, however i just logged on to the snapshot today and it is not and varies, i have not logged off, the first time i did die, and running back to house door was gone.
second time i just went out exploring and on return the latest door and stairs i had made were gone. i used oak and birch. doors in 2 locations in room were missing as well as 2 oak stairs. room is 10x10 and the two stairs went down into a small side room.