Depending on where you live, the dealership can try to fix it a few times before you can enact the lemon law or its equivalent if they cant fix it. Maybe the hatch lock is just jammed, shouldn't be too hard to fix.
Keep us updated on the solution in case someone else runs into the same problem.
We have had the same exact problem. Twice. Covered under warranty both times. First time when the car was 6 months old, and just this week at 2 1/2 years old. The first time it took the dealer multiple tries to diagnose since the problem was intermittent and hard to pinpoint. They ended up replacing the latch assembly, hatch harness and the body control module. Now at 2 1/2 years old it happened again, except this time it was totally inoperative. Turned out to be the release switch. Just picked it up today and everything is fine.
Seeing this thread that was started already, and what we have experienced, I wonder if this problem may be more common than we know.
Needless to say I am not very confident about how long the latch will work this time.
Did they at least show you how to open the hatch from the inside if you ever need to? There's a plastic plug at the bottom you can remove then you can insert a 3/16" screwdriver in the square hole and turn clockwise. I'm sure the dealer has the right tool for this...
Got the Trax back this afternoon. The diagnosis was that the wiring connector for the latch had 3 pins that were not making proper contact and were replaced according to the paperwork. So I guess you would call it a bad connection, which could explain why the problem was intermittent.
Unfortunately ¼" is too small and ⅜" is too big. If you take a flat screw driver about 9mm wide or .36" and insert it diagonally from corner to corner in the square hole turn it counterclockwise about 10° it will work nicely .
As for the switch it is quite possibly a dealer item or ACDelco supply store. About $15 at the dealer.
Well I guess I should note Just so anyone else that searches for the problem. The rear hatch on my 2018 Red Line LT now refuses to open. I closed it yesterday morning, and it acted like it didn't latch, so I pushed on it and it latched. Now I can't open it and the "Rear hatch open" message is on the dash. Luckily I can just hit the "Menu" button on the stalk and it bypasses. I am glad there is no warning noise connected with it. It will be going to the dealership later this week when I don't have to work. I will update what they find. Thanks for the heads up on how to manually open it Traxy.