I was worried this one would be really hard to make a test case for, but apparently not.

Descriptive Problem Summary:
I'm really not sure exactly what's going on here, but it's not right. RenderIcon()ing multiple turfs (through the use of vis_contents) containing objects with a PLANE_MASTER working on those objects causes them to render incorrectly. See the test project below.

Code Snippet (if applicable) to Reproduce Problem:
https://gofile.io/d/5kYIdJ

Expected Results:
The rendered icon should look like the actual world.

Actual Results:
Only one of the directional objects renders, and it's in the wrong place.

Did the problem NOT occur in any earlier versions? If so, what was the last version that worked? (Visit http://www.byond.com/download/build to download old versions for testing.)
I believe this is present in all 515 versions.

Workarounds:
None I know of.