to improve performances of 3D codes the grassy part of the scene has been arranged in ~15k boxes hierarchically organized as
object grassyscene → object boxes (~15k) → groups of plants (~10 per box).
Two additional files are then released for the models which can benefit from this rearrangement: grass_grid.zip. Please see also the comment on the head of the ".def" version, which includes a note on the ".obj" version (point 4).
Apart of this reorganization, with respect to the first issue of the scene (specifically grass.all.def), there is no change with respect the 200k plants to be instantiated which is still completely valid.
For what concerns the overstorey, we found that some boxes (172 of 48847) produced warnings. They are listed in the file linked list_tree_warning.txt and we advise to comment them in the corresponding tree plant files, given you get the same issue.