Copperhead Heatbreak for Ender 3, Under extrusion issues

[Phill1337]

Hello everyone,I recently got a copperhead heatbreak from slice engineering for my Ender3 and have massive under extrusion issues with a grinding extruder wheel since. Switching back to the standard heatbreak solves the issue so it is definitely related to the copperhead. It seems to me to be some kind of heat creep issue because when i pull out the filament immediately during the print it seperates above the heatbreak but lowering the temperature to as low as 175 °C does not solve or even mitigate the issue (with PLA, PETG has the same issue tho). I suspect the junction from the teflon tube to the heatbreak to be the culprit because i have some kind of edge that catches the filament there and i can only get it in by sharpening the end. The filament has a higher resistance to sliding after that point but not so much as to cause the under extrusion by itself.I tired changing the bowden tube and tapering the end with a pencil sharpener to facilitate a more smooth junction (consecutively). No dice.Thermistor and heating cartridge are new.The extruder has a extra heat sink to prevent overheating of the extruder gear.The bed is leveled via ABL before every print and also manually.The copperhead is installed with thermal paste into the cold end.The only thing i can think of is more airflow over the coldend but the copperhead seems to work for other people with the stock ender3 so that should not really be necessary.Thank you for your help.Regards,Phillip