Been a long time since I've allowed Cakewalk on my system, but from what I recall, I would:
Change the DRIVER MODE to ASIO - not sure if related but better than WASAPI re latency.
Keep in mind that ODD numbered channels go LEFT, EVEN numbered channels go RIGHT.
IOW - USB Channel 1 is the Helix LEFT channel, 2 is RIGHT.
OK, I was curious what's new in Bandlab Cakewalk land, the new SONAR version, so I installed the FREE version.
Set DRIVER MODE to ASIO.
Track Input to Helix 1+2 S.
Set up a simple Helix Preset - Amp+Cab, Ping-Pong Delay, Stereo Room Rvb.
As you can see below, it's recording in STEREO.