Just installed a BLTouch sensor on my Ender 3 Pro (using firmware version:
Ender-3 Pro1.1.6BLTouchV3.1PowerLossContinueEnglish), it all works great but each time I set the Z-offset I need to add it again. I home it, it requires -2.9 mm to get a paper sheet thickness from bed so I added that to my 0.00 Z-offset.
When I did a test print, the nozzle was way above bed, so I home the head, moved the Z axis and once again it is 2.9 mm to the correct location. Added this to my Z-offset again... been doing this now for a while and my offset is current at 11.2 mm! I did it on the screen and saved, hence up to 11.2 on the z offset now. If I power off and back on it once again is 2.9 mm from the correct location?