ID:2575426
 
Not a bug
BYOND Version:513.1523
Operating System:Windows 7 Home Basic 64-bit
Web Browser:
Applies to:Dream Seeker
Status: Not a bug

This is not a bug. It may be an incorrect use of syntax or a limitation in the software. For further discussion on the matter, please consult the BYOND forums.
Using a matrix as client color is also broken since 1523 when using render_targets.
sending a test case
Have you retested in 513.1525? There's another fix for client.color in that build.
I'm seeing the behavior change between 513.1522 and 513.1525, but the current behavior does not appear to be a bug. It appears the client.color value is being applied twice--matrix or not--and that's because it's applied to the object that's used as the render source as well as to the object using that source. Because in your project neither of those objects uses NO_CLIENT_COLOR, this is the behavior I would expect. It appears the real bug is in 513.1522 and it was fixed by the client.color changes.
Lummox JR resolved issue (Not a bug)