Creality's latest Sonic Pad update, v1.0.6.46.25, includes an internal M600 macro for a filament change, which will conflict with any custom M600 macro the user has included in their config. As such, the user is forced to remove their own M600 macro, if they have one, due to the conflict. Because the Creality macro is not accessible to the user, it cannot be tweaked. And, to make matters worse, it has a bug related to max extrusion distance, so you cannot successfully print a model with a filament change with this update installed.
The below workaround shows you how to go back to using your own M600 macro by renaming it, and how to create a modified Cura Filament Change post processing script to insert this new macro instead of M600.
In your Sonic Pad printer.cfg, add your own M600 macro back in, but name it CUSTOM_FILAMENT_CHANGE: