Problem with Quixel mesh texturing, "holes" in mesh?

I’m trying to use Quixel Megascans assets and I’ve created a material for a number of different small wood / tree debris meshes. However there seem to be some gaps or holes where the material is see-through, when I apply it to the mesh. I suspect something wrong with UV’s or texture projection but I don’t really know how to fix it. Has anyone else come across this? I’ve included some pictures that should illustrate my problem. I’m using this free asset Quixel Forest Debris