I have enchanted a sword as in the image. It appears like the sword is being held down, like the attack cooldown, but it doesn't come back up. If I left click with the sword it swings and the tip of the sword can be seen, showing that the sword appears like it's on cooldown.

As soon as i switch to the sword it appears for a second then gets pulled down.

I am not sure if this is intentional or not.

The only mods I had while testing were Fabric API and Spellbound Enchantments 1.3.0

Oh I see, thank you for the clarification

It is an unwanted consequence of frequently updating a jousting weapon's nbt data, which in turn is a workaround for servers being unaware of an entity's velocity when they are grounded. It is a known issue, but as it is a purely visual and low priority issue it will remain unaddressed until a better solution to the underlying problem is found.