My first post seems to be too laconic. Suppose I want to set up a spacey reverb pedal that could function before or after TF. I connect the cables and start it up.

Pre/Post global setting works fine for usual TF delays. I could set TF for Pre and get the reverb going just for the delay trails from TF. But then I switch to TF looper and record a dry phrase.

Now, unlike with the delay trails, I can’t add any reverb to the loop anymore. As brock mentioned, I suspect it’s because the inputs are summed to mono.