Overview: I use an M13 normally without any issue running into a Fender Blues Deluxe Reissue. Read about the 4CM method and wanted to test it since the Blues Deluxe has an effects loop, so I ordered a pedal snake. Got everything set up where it tested fine without adjusting where the send/return fell within the individual effects (FX) banks (i.e. Pre-all). So, then I went into the M13, set up a new scene for testing. For each FX bank, I dialed in the same effects: phaser, chorus and flanger at default settings so no matter what effect bank I chose, each effect would be at the same settings. I tested this and each bank played each effect properly. (in order, bank FX1/phaser, bank FX2/phaser, etc.) I then went into scene setup and set the effects loop for PostFX1, and went to test the difference between the effect in FX1 and FX2. Immediately I heard that FX2 was not applying the effect. The same occurred for FX3 & FX4. I then tested the chorus and flanger similarly - FX1 played the signal with the effect applied while FX2, 3 & 4 played the signal without the effect. I can't figure out why this is happening - I am guessing it is some simple setting but can't find it. Can anyone help?