As the filament is loading and unloading this cause the PTFE tubing to move and add a ever so slight pull upwards on the ring inside the fitting, this causes it to get stuck on to the tubing, making the standard method of removing the tubing by press in the raised gray section almost impossible.

This tool will help and make it easy to remove the tubing by allowing you to twist off the small gray cap that hold the assembly together, allowing the tube and the ring come out together.   This will allow you to remove any broken filament and or the 4 to 1 adapter.    

I made mine from PTEG, position in the slicer with the back of the handle against the build plate.

To use, insert the tool over the tubing, with gentle downward pressure on the tool slightly rotating back and forth, you should feel it catch on the ears.  When you feel it catch,  grab the tubing with the other hand and add slight upward pull as you rotate the tool counterclockwise about a 1/4 turn, you should feel a slight click as the cap unlock.  The tubing and cap should lift away with the tubes attached. 

To reinstall use the tool to guide the cap down, giggling a bit then do a 1/4 turn clockwise, you should fell a slight click as it locks into place.

Here is a video link to a video of how to use

This is a shows the older bulk version but the process is the same...

https://www.instagram.com/reel/DY-xT8bhi5B/?igsh=MW9senA5Yzh4OGI0Zg==