I've tried to hook this up 3 times and it doesn't matter what I do, when I mix blue and green I get more green and no cyan. I'm stuck in my tasks progression because I can't mix black paint without cyan, magenta and yellow (so the AI said...)
Steps to reproduce this bug:
Grab a blue pipe and a green pipe and hook them up to a color mixer to make cyan. If the bug reproduces you'll get green as the output, not cyan.