Okay, this is a bizarre one. This was brought to our attention by a customer. When importing some SRTs, UE4.8 is ignoring some atlas textures. It doesn’t happen with all the trees, nor all the time with the same tree. For instance, if you attempt to import all the SRTs from our free sample trees at the same time, the Broadleaf_Mobile leaves texture ends up black. But if you load the SRT on its own, the materials show up just fine. Or if you load the atlas textures first, then load all SRTs, the materials show up just fine. Then what’s really strange is you can delete everything you imported and then import the group of SRTs again and the material shows up just fine. What gives?
I was able to reproduce this internally and have entered a report, UE-16936 for reference. I will keep you informed as we investigate a solution.