A potentially wild edit cell is a cell that has the default values and no landscape or references attached to it.
Their landscape is flat (since a heightmap is not defined) and they have water at the default height.
This can happen when editing worldspaces with Creation Kit.
By themselves a wild cell edit is harmless, unless the coordinates are way outside the usual playable area and thus also expanding the worldspace bounds beyond the usual values. In that case it is a good idea to remove the wild edit cell(s) and correct the worldspace bounds to normal values.
Problems can arise if two or more plugins add cells for the same coordinates, wild edit or intentional. In that case the message Duplicate Cell is printed to the log.