I've experienced a similar issue.
 
	I haven't seen your code, but if you enter this inModBlockStateProvider.java,
 
	it should fix the problem you're facing!
 
	I hope your problem gets resolved!
 
	 
 
        makeCustomFlowerBlock(ModBlocks.CUSTOMFLOWER.get(), "customflower_bottom", "customflower_top");
    public void makeCustomflowerBlock(Block block, String lowerModelName, String upperModelName) {
        Function<BlockState, ConfiguredModel[]> function = state -> customflowerStates(state, block, lowerModelName, upperModelName);
        
        getVariantBuilder(block).forAllStates(function);
    }
    
    private ConfiguredModel[] customflowerStates(BlockState state, Block block, String lowerModelName, String upperModelName) {
        DoubleBlockHalf blockHalf = state.getValue(TallFlowerBlock.HALF);
        List<ConfiguredModel> models = new ArrayList<>();
        if (blockHalf == DoubleBlockHalf.LOWER) {
            models.add(new ConfiguredModel(models().cross(lowerModelName,
                    new ResourceLocation(TutorialMod.MOD_ID, "block/" + lowerModelName)).renderType("cutout")));
        } else if (blockHalf == DoubleBlockHalf.UPPER) {
            models.add(new ConfiguredModel(models().cross(upperModelName,
                    new ResourceLocation(TutorialMod.MOD_ID, "block/" + upperModelName)).renderType("cutout")));
        }
        return models.toArray(new ConfiguredModel[0]);
    }
	 
 
	modblocks.java :
 
    public static final RegistryObject<Block> CUSTOMFLOWER = registerBlock("customflower",
            () -> new TallFlowerBlock(BlockBehaviour.Properties.ofFullCopy(Blocks.PEONY).noOcclusion().noCollission()));