Parking brake sticking.

2017 Gen 2 Diesel Manual.

Has happened 3 or 4 times now. Apply brake for a few minutes and go-to leave and release hand lever and brake definitely still at least partially applied. Can get it to release by holding button down on lever and quickly working lever back and forth. What's the most likely..cable sticking or something in the caliper itself? Best way to differentiate between the two? When it's sticking I can feel in the lever that there is free movement before it starts pulling the cable. Any tutorials on how to change cable? A new OEM cable is less than $40 so I'd like to fix this before I forget some day and apply it and get stuck somewhere. It's a 6 speed so I actually use the parking brake.