The Bluesound Node 2 can indeed pass an MQA signal via optical. From their website:
Bluesound Players are a full MQA playback solution. They will decode and render MQA playback up to 24/192. If however you are connecting an external DAC, the maximum output will be 24/96 and MQA processing is not happening in the DAC.
If you have an external DAC that is certified by MQA, you may bypass Bluesound's MQA rendering process in the Bluesound NODE 2 or VAULT 2 and send the pure untouched music bits directly via TOSLink Optical or Digital COAX output for processing by your external DAC.