Mesh Bed Leveling in Marlin causes wrong X,Y positioning



Hi all,

I’m using an ANET A8 currently without probe sensors. Having recently upgraded to Marlin 1.1.8, I decided to try the Mesh Bed Leveling feature (enabled in config file before flashing) since my aluminium heatbed is slightly warped in the middle (bowed ever so slightly upwards).

After performing the G29 probe via the LCD screen for the 9 spots on the bed, I saved the mesh to EEPROM and added M420 S1 after every G28 I have in my start gcode and ran the print. However, what I noticed is that while my priming / cleaning line of extrusion works fine, the print head goes and start printing at the wrong place entirely when the actual print job starts.

My start gcode:

Basically, everything above works fine, but when it starts printing it goes way off as seen in the image here.

May I know how I could go about troubleshooting this error? Thank you.