Just checked a few more assets from Chaos Cosmos.
It's just a big mess all over. Opacity maps missing or in dfiferent places. Chaos needs to update the libraries before any useful vegetation is provided. Maybe just a Mac issue.
Attachment:
Chaos Cosmos tree:
Opacity map in the IOR slot at a value of 3 ? After checking a few more vegetation assets did not see any correct one. Either maps are missing or materials with weird settings.