Chunks missing from maps

Most every time I create a map, there is a chunk missing, I have tried recreating maps to see if that would fix this issue but that did not work. Attached is a screenshot of a wall that I have put maps on to make one giant one. there are black squares on that map that are chunks that are not missing from the landscape of the world. and just so you know, I searched the database before I created this one, and I found nothing similar.