explorer maps, when placed in an item frame, display a green marker to represent the item frame in the corresponding corner even if that item frame is far from the map.

When explorer maps are placed on an item frame, the green marker appears on a corner of the map even if the item frame is not within the map boundaries. This causes alot of false green markers in map collages. In the two attached images (one of which is a bit zoomed out to see the extra green marks), there are multiple green markers for the item frames in the map collage.