I loaded my world in Optifine 1.18.1 and encountered this light issue, only a having a light source our vertical skylight fixes it, but it came back when the light source was removed. Though, if I loaded the world in vanilla Minecraft with the light source still there, even after removing the light source, the area where the light propagated becomes normal. I re-created the world in vanilla Minecraft alone and the area with the light error was resolved, so either you have loaded it in some mod like Optifine or Optifine, or the issue is inconsistent.
Sohm Anchan
I loaded my world in Optifine 1.18.1 and encountered this light issue, only a having a light source our vertical skylight fixes it, but it came back when the light source was removed. Though, if I loaded the world in vanilla Minecraft with the light source still there, even after removing the light source, the area where the light propagated becomes normal. I re-created the world in vanilla Minecraft alone and the area with the light error was resolved, so either you have loaded it in some mod like Optifine or Optifine, or the issue is inconsistent.