Running 15.04.2, Windows 10 64-bit
I had a part that has more pieces than could fit on the build plate.
Did the first bunch of these pieces, all identical, with no issues. Essentially 6 "L" shaped pieces
Had to wait a few hours to delete those pieces off the screen, then drag the remaining pieces onto the Cura buildplate. (Ultimaker Original w/ Heated Bed)
Made sure the first few layers went well then walked away.
When completed, these pieces were all sloped. Not perfectly straight, vertical pieces. No issues I can see with the printer, belts are fine. Never had this happen before. Here's how they came out.