rebound adjustment doesn't click

Over many years and bikes I have found this to be a common experience. I am not sure of the cause but often times being very careful will produce a slight but recognizable feel to the click which is made a little easier to detect by marking where the click should occur vs the screw head alignment. Servicing/cleaning the clicker unit may help for a short while but basically I wouldn't worry about it. Worst case, just use your turn it in then out routine.

Little check ball and spring in fork cap may be sticking or someone may have used too much loctite on the top of the cart rod upon assembly and it fouled up the spring and ball maybe.