BL touch Failure of last leveling probe

I am using an ender 3 v2 with BLTouch. The motherboard is a 4.2.2. My version of firmware is Ender 3-V2-BLtouch-20210219. When I run a bed leveling test all points seem to read well but when I begin a print and the bed leveling runs the last point X220,Y220 often reads 12.6 while all the other points read considerably lower about 7.7. Presumably this messes up the BLTouch leveling. Is there a fix for this?