Bugs with light

Good afternoon Mojang! 
I have been playing Minecraft Bedrock for a long time, and for at least several months I face a very annoying bug that prevents light from proper working. Some chunks just keep being dark even after I place sources of light. If I build a vertical structure, this bug stops from appearing, but I cannot cover all free space on the map with structures. I attached some screenshots so you can observe the issue yourself.