Black spots on map

Since MCPE-162421 was resolved 2 years ago, and this bug being slightly different, I am reporting this as a new issue

I found an old map and noticed some parts of the grass were displayed as black instead of green. When I attempted to reload the chunks and also make new maps, the blocks would remain black. However, when placing a block on top and destroying it, it fixes that one block, however this is tedious.