It seems that even after cloning a mesh, all clones are still sharing the same Thin Instance capabilities, i.e. make 10 clones, create Thin Instances for each of them, and only the last call to
mesh.thinInstanceSetBuffer( 'matrix' , ... ) produces something, previous calls seems to be overwritten.
Use case: I’m currently planting tree on a rather big map, each map sector having its own set of Thin Instance (so a sector can be turned off when it’s too far away).
Playground demonstrating the bug: Playground.
It’s based on the example with four cubes, but here the blue and green cube are not based upon a freshly created cube, but from a clone. The bug removes the red and yellow cubes as soon as the clone calls