When loading a brand new seed, the light levels from areas that would normally have light or no light will appear in the world. It's only until that light source block has been block updated that it will use the updated light source.
This means, if a regular ice block is placed near an area that still has that light level around it, the ice will melt, though there's not any lava near it.
These images shows light levels in areas where no light emitting block or torch has been placed.
When loading a brand new seed, the light levels from areas that would normally have light or no light will appear in the world. It's only until that light source block has been block updated that it will use the updated light source. This means, if a regular ice block is placed near an area that still has that light level around it, the ice will melt, though there's not any lava near it.
These images shows light levels in areas where no light emitting block or torch has been placed.