Recently, mobs, entities, and certain blocks' transparency have been broken by a recent technical update while using Vibrant Visuals at 50% resolution.
In a normal case, if the player’s screen is too close to mobs, entities, or certain blocks, Minecraft will automatically lower its opacity, making it slightly transparent, which is how it's designed. However, due to a recent hotfix, the feature was messed up specifically in Vibrant Visuals, where if a player does the exact same things, instead of making it slightly clear, it causes a chaotic/disturbing texture of the mob/entities without any resource packs or behavior packs in use.
This might not be a problem for high end devices that can handle resolution above 50% without lowering other options, but for upper mid or mid range devices like mine, it's annoying.
Regardless, please solve the issue as well as the other Mojang Support!
Disclaimer: this bug only appears when using Vibrant Visuals, specifically at 50% resolution. Other options, such as shadow quality, fog, etc, do not remove or cause the glitch, as far as I'm concerned.
Steps to Reproduce:
Enable block and mob dithering in Settings > Accessibility
Enable Vibrant Visuals in Settings > Video and set the Resolution to 50%
Stand near sugar cane, glass panes, or a mob/entity
btw it also affects glass panels