Previously we imported just a partial package for the environment prefabs (House, hut, trees, and the crate). Those are also contained in the (more) complete package, but not recognized as already being there, so “import all” overwrote them.
Partially (on my system) that was due to different line endings, but there were some changes that would have gotten lost had I not taken care to check it. In particular I set the buildings and trees to be static objects in their prefabs (where settings like that should be), and also had the navmesh obstacle component added on the crate.
Sorting this out was somewhat tedious, I hope there won’t be an even more expanded “Synty Polygon Student” package to import and further imports don’t overlap…