As I understand it, on the Max-9, this wasn't an exit, but had a special non functioning "door"?
Essentially a blanking structure located and attached to the fuselage as a door in the same position would have been.
On the Emergency Exit version the frame is beefed up to allow for the additional forces imposed buy the sprung loaded hinge and subsequent slide deployment and also to allow for the fitting of assist handles either side, but aside from a few extra.components this plug or door or plug door or door plug is essentially a door that can be opened using tools but serves limited purposes beyond maintenance access.
The basic latching and locating mechanism is the same for any door fitted in this position. The difference being that instead of cam locks it uses four wire locked through bolts to keep it in the latched and secured position. By virtue of how and where they are fitted, one such bolt would be sufficient...
So either someone screwed up in production or during the post delivery work at Alaskan... There's ten days clear between delivery and entry to service. Every aircraft regardless of manufacturer or customer arrives from the factory and goes into the hangar.
There's a whole list of stuff that has to be done from basic snagging and rectification to airline specific software/post production modification/fitting and checking safety equipment and markings etc.
And this aircraft was in the hangar overnight on January 1st. As bourne out by flightradar24.