I have the Chameleon working and swapping filament fairly reliably. But... on the second or third layer the hotend inevitably clogs. When I disassemble it and have a look, I find a ball of PLA "lint" in the neck of the heat break - - basically the result of the filament stringing when retracting and then getting wadded up. I can just remove the lint with tweezers and that clears it - there's no clogging in the nozzle or below the neck of the heat break.
I know Bill and probably others have spent a lot of time tweaking to avoid these types of problems, so I'm hoping to get pointed in the right direction for things to try.
For reference I'm using a V6/Volcano so the heat block is longer than other hotends. So I've tweaked the unload gcode to increase the distance the filament is "plunged" but that hasn't helped. I'm extruding at 205 degrees. Using a BMG clone as a Bowden.