This happened to me for the first time using old PLA on a very hot day. I think your diagnosis is correct.
Due to warm enviroment AND all the heat from nozzle, housing, etc. the filament becomes already soft in the extruder. This results in clogging the extruder / jamming the AMS.
I have an enclosure and am running into this. eSun PETG that I have had for a while, in the sealed original package. Was jamming every time.
Made the mod shown by @StreetSports, had one successful retraction.
Just jammed in a coupling approaching the filament buffer; pics attached. Definitely deformed.
Going to try an aquarium air pump and adding a cool air supply to the area subject to heat-creep.
Also thinking about adding an enclosure temperature sensor and some kind of temperature limiting (exhaust port or fan with low or zero flow when off, to build enclosure temperature?) to prevent heat creep. Though thatās quite a bit more effort.
I think you closed/posted before the images finished processing.
Fixed the image uploads.
Need to figure out a rotary joint? for the cool air tube connection. Though itās probably OK for it to leak quite a bit.
Iāve had āFailed to pull out filament from the extruderā once before with Bambu PLA matte brown and just unpacked galaxy purple and had this on my first print. It really seems like the heat is not dissipated on the cold end and the filament softens and when the gears from the extruder push back the filament after cutting it bends and get stucked. Iāve got it unstuck by extruding a little and then manually cutting and manually pulling back from the AMS.
Althought it CAN be that my bowden is having some resistance for the filament to be pushed back.
