If the bed is clean (it will absolutely detect small particles under the bed), it can help to double check the overall height of the 4 screws.
This is simply using the klipper screw adjust macro, which gets the 4 corners level. If they are out of plane with the center it may still have bowing.
I’ve learned elsewhere you can raise or lower all the screws then skip along in the procedure to the probing step. If the center is above or below the center.
Maybe the routine could be improved to measure the center point as well. 
I find it a little tricky to judge the step where the nuts are flush with the screw caps.
But mine has always been <0.2mm out of the box.
Your mileage may vary.