Lighting glitch

Sometimes when I play in my survival world or in LAN servers, When I enter the "End portal" or "Nether portal" and exit I notice there are issues with the lighting some parts of the world have dark lighting and some parts are fine. This bug doesn't only occur when entering a dimension and exiting. It also happens sometimes unexpectedly. I've experienced this in 1.14 and experienced it still when I joined the Beta 1.16.0.57. I use a texture pack but it's not the texture pack. I've experienced this bug even without the texture pack enabled. But, I've also experienced a lighting bug not just the bug where it goes dark. I've entered the Nether portal in my survival world and when I exit the portal, It was night but it was very bright like I had night vision on me but I don't have a night vision potion.