I found it! The Treasure of the Sprinkler Madrea!
Been dealing with this since I bought this house 26 years ago. Not sure how deep the previous owner installed them, but I've had to raise most of the sprinklers to get them back to ground level.
This one was 2 to 3 inches (55 to 75 mm) deep. Had to dig a trench to find the supply line, then follow it back to find the sprinkler.
New one is now at ground level.






