So two places to check that the two conditions you need.
[1] hit Sel on Ch 22 and check you’re in “Processing”. Press the Fn Button which takes you to the page where you set the source for each channel. Tap on Ch22 and make sure it’s Yellow (hi dSnake if it’s not).
Press Fn again – note that the gain knob on the Processing page should be yellow
[2] Routing. Press Setup, i/o patch tab and the dSnake In tab below. Tap on Ch 22 then use the rotary encoder to scroll it to 14. Apply then perss setup again and you should be good to go.
I know you probably did all this already but sometimes it helps for someone else to list it out.
The only other thing worth checking is that you haven’t got a PAFL engaged somewhere else.
Let me know if you fixed the issue.