Probably one of the most annoying bugs I've found, I don't have optifine installed but idk what's causing the problem.
video link: https://www.youtube.com/watch?v=G7YYDSrPYV8
every mod I have downloaded at this moment:
securitycraft, arkifs hoverboard mod, baubles, betterblink, betterfps mod, bookshelf, brandonsCore, chisel. chunk animator, clumps, codechickenlib, colossal-chest-mod, controlling, CTM. CycolopsCore, draconic-evolotion, EnderCore, Ender IO, engineersdecor, foamfix, GLASS, gravity gun, heroes expansion, Hwyla, ICBM-classic, iChunUtil, infinity, jei, journeyman, lasermod, llibary, lostcities, lucraftcore, mantle, matteroverdrive, mcw-bridges, performant, morph, mowziesmobs, parabox, prestige, projectintelligence, pymtech, redstoneflux, renderplayerAPI, rsgauges, secretroomsmod, shatter, speedsteer-heroes, Sync, Tconstruct, techguns, Uslabs, Vanillafix, wordedit
Mods I know that isn't causing the issue: Performant, VanillaFix, Prestige, Betterfps mod, and Foamfix
Thanks if you know how to fix this.

this also happened with wireless extensions btw, I made a full square with them, and sometimes when I look in certain directions it turns off and it only happened on the right side of the screen. No problems with the left, just the right. Weird.