Written books do not maintain CustomModelData NBT upon creation

Textures: (I have tested each texture and model individually)
Purely Vanilla.zip
Items:

/give @s minecraft:writable_book{CustomModelData:1}

/give @s minecraft:written_book{CustomModelData:1}

Here is a video to better display what is meant. When signing the writable book the CustomModelData NBT data is not transferred to the created written book.