I've found a downright weird issue with Minecraft 1.13.1 where any block with a .mcmeta file attached in a resource pack that uses a different one in Default just shows up as a blank texture. I've tried removing shaders and launching without OptiFine and it still has this issue. It did not do this in 1.13 or any version before it. Pictured here is Coterie Craft and the blocks shown are the Sea Lantern and the variants of the Command block. The 32x version is just fine but the 16x version has this issue. It's not exclusive to Coterie Craft though.