I have never had this issue before!
I've been switching between front input (when recording guitar) and SPDIF (when reamping) for years
But yesterday suddenly when I wanted to switch to SPDIF I couldn't get signal from computer...
But then I accidently bumped into my guitar and heard the signal... FROM THE FRONT INPUT!??!?
Why is it doing this?! I switch back and fourth between the settings "front input" and "spdif input" and it makes NO DIFFERENCE