I don't know if this is related, but iSpot has a link to the relevant NBNG map on any posting with an ID offered. Naturally, iSpot uses a routine with the old URL format, but with the new Gateway, which has a different URL format for the grid map, you get an error if you click that link.
This will be a problem for any search engine and for any external website that has links to the old Gateway, and the implication seems to be that the webmasters first have to discover that there is an error, and then re-code their pages to fit the new one. For a resource like the Gateway, I don't think that is acceptable. It was an eminently predictable consequence of the change, and the Gateway code-writers should have ensured that these requests are redirected. I can't see that it would be an enormous task to write a routine to take the TVK from the requested URL and place it in the new format URL to display the map.
M.