Hello.
My A1 did the same thing, and I commented out the 2 digits in the gCode. However, I have always wondered what these 2 steps are supposed to do and what Bambu Lab was thinking.
For anyone wondering what this step in the initialization is for, I found an official statement from Bambu Lab in another forum and that sheds some light.
"Hello
Thank you for your patience. Our R&D department gave the following response. Before bed leveling, the extruder tried to extrude but could not extrude due to insufficient temperature. This is a normal process.
This aim is to extrude a filament section against the hot end, so that the bed auto-leveling data is more accurate. The relatively large print area of the A1 requires better pre-tightening of the hot end, which will not damage the gear after internal testing.
The clicking sound we hear is the sound of the extrusion motor losing step, which is a normal phenomenon.
I hope my answer will help you with the problem you are experiencing.
Please let me know if you have other questions or if I can assist you with anything else. We are here to help you!
Kind RegardsBambu Lab Support"
So, after knowing this finally I use the original Start gCode now again… seems to make sense 