I have the same issues you have:
The transpose function does not work as intended. I can hear the transposed note and the original. But in my case with a Strat, a PRS, a Tele... which means is not the guitar. No parallel path engaged. SPDIF Output set to Master Stereo. The same via the Rig controls as via the Transpose effect. Reset Init Globals had no effects over this. Os Version: Release 8.7.15.42312.
The Rig Manager can not found a Profiler message in my case only appears when the computer (a PC) has recovered from suspension mode. My workaround is simply unplug and plug the usb connector. Hope this helps.
have you tried to record the SPDIF signal on your computer?