I am attempting to upgrade a CoreXY printer, using a BTT SKR 2 Rev B motherboard, TMC2209 Drivers and a bltouch. After successfully setting up sensorless homing I moved on to configuring Bed Levelling, however, something has changed now and homing is not working correctly. When I start up the printer now, Marlin seems to assume that whatever position the X, Y and Z axis are in is 0. So now, after a G28 X Y command, the print head moves forwards and backwards about 10mm along the X-axis and then the same along the Y-axis. It is not moving to the corners of the print bed anymore. I can move the print head X and Y axis and the result is the same. Where ever the print head seems to be Marlin reads this as X0 Y0
Any suggestions would be most helpful

I just went through this today.
Make sure you have the DIAG jumpers in place for the steppers
See the circled pins here >>>> [teamgloomy.github.io]

I had the same problem in my MKS NANO ROBIN v3 and TMC2209 ... To solve this, I decrease the sensivity of sensorless