peter I haven't seen this so far. Can you make a screenshot of this white screen you mentioned?
The screen is basically the box you get to choose to where you want to save the backup except it has nothing in it , its blank, and i cant reproduce it again it recovered itsef after i did a database sucessfully , after that the full backup workrd as well, it did this with about 3 attempts innitially then i rebooted the ipad than it still did it once again thats when i tried the database backup and it worked after that.