As a quick thought on this even though I haven’t run into this problem yet as I’ve only had my v3 for a day; you can add some gcode to the end script. This gcode is pulled from lulzbot’s cura start script (set to 15mm):
G92 E-15 ; set extruder negative amount to purge
G1 E0 F100 ; purge XXmm of filament
You could change the E0 to E1 or just repeat it - basically select the toolheat. Then retract say 60 mm of filament. This should shoot the filament out of the extruder on quit. (Though you should probably warm the extruders up first, or find the right time to do this. But heating both up at the end of the print as the bed is cooling is probably the best time as they won’t ooze over your print, and then you don’t mess it up if the toolhead has been off for a while when it gets to the end).
That would set your printers to purge filament at the end of every print. You’d have to reload it every print, but you’d stop the clogging. You could set the profile for it to only happen with certain materials as well I’d think.