Steps to reproduce:
1. Create a level that contains a one-way arrow object (or any other object that can be resized both horizontally and vertically).
2. Set the size of this object such that the width and height are not equal.
3. Rotate the object.
4. Save the level.
5. Load the level again.
The width and height of the object will now be swapped. (You can save and load the level again to fix this.)
Thanks. It's fixed now.