The app switches fine. Let me explain; The Shortboard has Modulation and Delay already fixed on the pedalboard, and to my knowledge cannot be changed or assigned to different buttons like your FBV3. It's like the mapping in the amp software is wrong, and I couldn't find a way to change the mapping. Also, I tried this with 2 different Shortboards and 2 different data cables, so it seems like the issue is within the amp. I'm just trying to figure out from other users if this is an issue that I missed a fix for, or if it's a bug.
How do you remember which effect you assigned to which switch on the FBV3? That's the reason I didn't purchase it vs the Shortboard.