Few months ago I had same problem.
I write to support, exchange few emails, but they didn’t have a clue, whats going on.
I found by myself this: (copy paste from emails)
[quote]On Fri, Aug 28, 2015 at 10:53 PM, Aaron Cooper firstname.lastname@example.org wrote:
[color=#0000FF]If you wouldn’t mind sending me a project backup I can at least take a look. I doubt you did anything wrong, but I’ll see if I can’t find anything out of the ordinary. The Z-index is a long shot, but I figure it’s worth trying anything that could change the way this is displayed. Unfortunately, if that doesn’t fix anything and I can’t find anything wrong in your project, the only short-term solution will be to redo those rectangles with the path tool. Be sure to make liberal use of the ctrl + d command to duplicate once you get it drawn right [/color]
I tried with Z-order, but no difference…
But I found something else:
[color=#BF0000]If I change rectangle properties Stroke Style/Join Style to second or third option, then the strange behaviour is GONE. Rectangle is displayed normal.[/color]
Strange, isn’t it…
I found also this in the help:
The rectangle tool (rectangle) creates and edits rectangle shapes. To create a rectangle, select the tool and drag inside a window to create a new rectangle. Hold down ctrl to make it a perfect square. Once a rectangle is created, you can use the square handles to change the rectangle’s height and width. This is important because it is the only way to resize a rotated rectangle and let it remain a rectangle. If you resize a non-orthogonally rotated rectangle using the selection tool, it will skew and become a parallelogram, but if you double-click on it so that the rectangle tool is active, you can change the rectangle’s width and height using the tool-specific handles.
I think there is something in this… Because you can see, that these ‘strange’ lines looks like very skewed parallelograms…
I found also that if you change the rotation angle of the rectangle to 0.1 (or 0.01), then rectangle is also displayed all right (without changing stroke/join style).
Hope it’ll help you.