Hello,
I have the same setup and no problem. Why do you turn off MQA decoder in Roon? If you use volume leveling in Roon when you shuffle music, I do, it’s Roon and not 218 that is decoding the MQA and that is when I get the purple light. When 218 decodes I get green and blue light depending on the type of MQA. In your zone settings in Roon, 218, try the “load default “ and see what happens. Good luck

Main Room: iPad Air, 218, Roon Nucleus One, Qobuz, 500 CD, AC12, DSP6000.2 (2007) & IsoAcoustics Gaia I
Studio Ω: MacBook Pro,Traktor, Ableton Live, Push 3, Novation Peak, Korg MK, Akai MPK 25 & 61, SL 1210Mk2x2, Traktor Z2, A&H Qu-Pac, Genelec 1031A.
Bedroom: Roon, Wiim Pro Plus, Genelec
Photo: Leica M with 35mm
LESS IS MORE