If that's an option, the 1080p assets shouldn't be downloaded. You should be presented with a choice as to which texture pack to save downloads.I'm still at a loss as to the "optional texture packs" that someone is going off about. I can only guess that what's being referenced is to allow the user a choice in downloading 4K content so they have control over not wasting what may be limited bandwidth with assets that may never be used when the user is only running 1080p displays.
I don't think it is an option though as the 4K assets are used to create the higher quality 1080p experience. What was the game?