This bug only work in hangar and test range! 
-# In real match, the paint will replace with the module itself's default color 
Step.1
Build a robot as your color source. Also you should notice you have to install all part and pilot before edit its paint
Step.2
Create a new custom wrap, add a sticker or edit something to save it
Step.3
Then, open the paint preset you just created, click the "empty slot" for every module you want to copy the color. You can also use other paint or decal on it, after you done every change, save it.
Step.4
Apply the paint preset on the robot you want to paste, done
Re-edit the paint preset on other robot maybe cause the paint messed up. You have to edit on the your color source robot.
Show your art under the post