Does QC pass data entering its (traditional cable)Midi In port to USB Midi out by way of the 'Thru' function?

Trying to use a MorningStar MC6 to send via it’s midi cable through the QC via USB midi to an iPhone running Quantiloop.

I know Quantiloop is configured correctly as far as USB audio and USB midi from QC.
I can set up a QC stomp to trigger the midi on and off etc in Quantiloop but I can’t get midi sent to QC’s midi in port to make it to Midi thru via USB to the iPhone so I can set up the MC6 as a dedicated looper control and free up the QC stomp switches for other purposes…

Short version: does QC midi thru make use of USB the way it does via the traditional midi out/thru?