M600 stuck extruder

[sn4k3]

Currently with a Prusa MK3 and Volcano, after a M600 and if not swap filament in same moment (Let it cooldown to ambient) and then re-heat and swap filament I'm getting filament stuck in a cold area. Most of the times I can push it by tight the extruder, but on worse cases I have to drill extruder path with a sharp rod to make that plastic tip come out which is very bad situation, mostly it have ruin several filament change prints. Now can I prevent this?

I guess this comes from UNLOAD_FILAMENT rather than M600, but the unload procedure not optimal on my case.
Note I'm using PLA at 200/205ºc.