I have the separate issue of how the clutch doesn't actually engage: I sometimes cannot put the shifter into gear when the pedal is pushed to the floor (and then it also won't return on its own). For me, it's not just that the clutch pedal is sticking. It's that the pedal is occasionally doing nothing to engage the clutch at all.I thought I'd add to the conversation as I'm experiencing the same issue with my '17 diesel, 43K miles. Pedal occasionally sticks to the floor and won't come back on its own. I can lift the pedal up with my toe but hydraulic pressure does not return to the pedal.
If the problem keeps returning, I'll have Chevrolet roadside assistance tow the car to a dealership 2-3 times a week as necessary. I have a spare car to borrow from my parents, so I'll keep on repeating this over and over again until they decide they don't want to do it any longer.