The scenario is as follows:
I created a cube locally within Creality print 6.2 and expanded it to a 40x40mm cube using the scale operation.
Using the cut function, I include two connectors, one a snap in the centre, and one a frustrum plug towards a corner. Connectors are confirmed.
I then confirm the cut and move the resulting top and bottom pieces around, and reorient the top (female) part so that I can see the holes.
I save a single 3MF file, and also save a set of STL files.
I can then restart the software and load the files.
The 3MF file is fine. Two half blocks are loaded in the same location on the plate.
HOWEVER, of the two STL files, the male is fine, but the female has lost her holes, and has become solid.
I’ve also opened the STL files in fusion 360 and they are the same, male okay, but female is solid.
(the stl file for the female is also very small (2KB) compared to the male (84KB))
Hummmmm