Picked up our new Expanda outback 14.4.4 and we are finding folding up the bed end to be difficult. The mattress dosent fit inside the tent bar. This dosent seem to be right as the bar won't come down flat as it compresses on the mattress. It can be forced in putting a lot of pressure on the bar and mattress. Our mattress is a 50/50 split. Has anyone come across this?