Many textures are not loaded when the affected blocks have variants.

[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:tall_grass
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:dead_bush
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:fern
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:dead_bush
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:dandelion
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:red_tulip
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:poppy
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:houstonia
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:white_tulip
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:allium
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:pink_tulip
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:orange_tulip
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:blue_orchid
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:brown_mushroom
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:red_mushroom
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:snow
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:cake
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:waterlily
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:nether_brick
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:red_sandstone
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:grass_path
[10:47:32] [Client thread/WARN]: Unable to load definition minecraft:red_nether_brick

Example not working: minecraft/blockstates/allium.json

{
     "variants":{
     	"normal":[
	     { "model": "flower/allium",  weight: 80 },
	     { "model": "flower/allium1", weight: 1 },
	     { "model": "flower/allium2", weight: 10 },
	     { "model": "flower/allium3", weight: 9 }
	]
     }
}

Example is working: minecraft/blockstates/cobblestone.json:

{
    "variants": {
        "normal": [
            { "model": "cobblestone", "weight": 50 },
            { "model": "cobblestone1", "weight": 20 },
            { "model": "cobblestone2", "weight": 7 },
            { "model": "cobblestone3", "weight": 7 },
            { "model": "cobblestone4", "weight": 16 }
        ]
    }
}