When doing a route check (Route filter) the ECDIS might include ENC cells that are not required for the selected route. These cells might occur as "Not Up to Date" and "To be ordered", if these cells are not included in your portfolio. This is caused by the ECDIS using simplified polygons when defining the ENC cell coverage, whereas NAVTOR uses the actual cell coverage when determining which cells intersect with your PAYS area or route. Please also see attached document for more details.