Hello,
just started a new ladder char (paladin) on the ptr last week and leveled up to start of act 5.
When I resumed today it was changed to non-ladder. I have no clue why this happended, but unfortunately it did happen.
However, if this happens on live server later as well, this will be the supreme bullsh*t.
Please fix it. 
BR
/edit: also items in shared stash are gone, since I had only one ladder char running