Layer Shift after pause to insert metal plate

Bambu Lab A1 Series Troubleshooting
1

I have a consistent layer shift of ~0.1mm in Y direction after using the following layer-specific G-Code

M400 U1
G28 X Y
M106 S255

I use Orca Slicer and tried both 0.4mm and 0.6mm nozzles.
No AMS

2

I have the same issue, P1S no AMS. I initially tried that custom G-Code after noticing there was always a a slight gap between layers after adding a pause in the slicer. The slicer shows a grey line for pauses when the model is sliced, and without fail that grey line would show up on the printed model as a weakly bonded layer that I couldn’t sand to remove as it went right through the model, as though the z height was ~0.1mm too high. Models would always split from this layer too if forced.

Using the custom G-Code to add a pause and home just made the layer shift on the x-y axis instead.

Forum posts from 2023 indicate it is a firmware issue, but it has clearly not been fixed.