I just find out the problem with the bottom case longer than the top case !

It was not a openscad render error (as I thought naively at first) but I imported the 4 buttons version of the Adafruit case for the bottom (and not for the top) which is longer than the 2 button version !

I’ve changed the import directive in bottom.scad file, fix elements position and all seems right.

I’m thinking to add a support for the screen (because screws are not holding very well in plastic) and send it back to print again.