Multiple Build Plate bug PrusaSlicer 2.9.0
I found if you have multiple build plates, there's a void on the first layer surrounding the plate number in the lower left. Once you slice, if you check the first layer, there will be a rectangular area with no extrusion. It effects STLs and parts you add from within the slicer.
RE:
I tried replicating your issue by putting an object from the gallery on the bed and copying it twice (total of 3 objects). I then dragged the copies onto their own print-bed. Then I put all three objects over the number on their respective build plate, sliced, and then inspected the bottom. I don't see any areas of missing geometry.
If you are able to duplicate your issue and save it out as a .3mf, please post it here (after zipping into a .zip file to keep the forum software from silently ignoring your attachment).
Also, what computer environment are you running? I'm on Win11 and it seems to work here or I'm not duplicating the steps to cause the issue.
See my (limited) designs on:
Printables - https://www.printables.com/@Sembazuru
Thingiverse - https://www.thingiverse.com/Sembazuru/designs
RE: Multiple Build Plate bug PrusaSlicer 2.9.0
Its a known issue. Its also just a preview bug, the actual gcode is fine. Its also been fixed in 2.9.1
Original bug report on the Prusa Slicer github https://github.com/prusa3d/PrusaSlicer/issues/13814
From the 2.9.1 alpha release notes -
Bugs fixed with respect to 2.9.0
Fixed rendering of bed numbers in Preview so they never render on the toolpaths. Also, the bed numbers newly show when viewed from under the bed. #13814