Sorry my bad its not Forge its the Anvil file format. So when the game converting old maps to the Anvil file format then happens this. (i will fix the description) sry again.
True you dont need, but sometimes it's good to have and easier for me too.
I think you should put it back :S 😃 but its your choise i know 😃
It's a Graphical glitch not texture problem. its not rendering the side where the block is so i think is a rendering bug!. =] i have another bug but its hard to write down. :S
I searched for it but I didnt found sry.