This Reddit post i made this day was to ask around if people knew what caused "strange white lines".

turns out they are caused by Refraction.

the post also includes a modlist so i cannot really give more information

alright i just have LibrarianLib installed (these names) and it doesn't cause the issue, only when Refraction is also installed.

Do you have any existing refraction items placed in your inventory or any refraction blocks placed in your world?

nope. i didn't even place a furnace yet.

just having the mod installed caused this

Refraction doesn't do any custom or funky block related rendering at all. Could you try removing refraction but keeping LibrarianLib in your pack and see if the problem occurs?