The .json file for double_plant is malformed. It is missing commas, and duplicates keys for the "variants" object.
Code below from latest snapshot:
{
"__comment": "Fair warning, this format is highly likely to change even more in the future!",
"variants": {
"bottom": { "model": "double_sunflower_bottom" },
"top": { "model": "double_sunflower_top" }
"bottom": { "model": "double_syringa_bottom" },
"top": { "model": "double_syringa_top" }
"bottom": { "model": "double_grass_bottom" },
"top": { "model": "double_grass_top" }
"bottom": { "model": "double_fern_bottom" },
"top": { "model": "double_fern_top" }
"bottom": { "model": "double_rose_bottom" },
"top": { "model": "double_rose_top" }
"bottom": { "model": "double_paeonia_bottom" },
"top": { "model": "double_paeonia_top" }
}
}
Good thing the file isn't actually used by the game, then.