Problem importing official Vélodyssée GPX file on web or android - only single section imports

We have greatly appreciated C. T. on our family-of-4 cycling adventures over the last few years. We recently completed the Vélodyssée section between La Rochelle and Nantes, and had trouble importing the route GPX files in cycle.travel, downloaded from the official route website. We could load small sections fine (e.g. La Rochelle to Marans or Marans to La Tranche sur Mer, example https://www.cycling-lavelodyssee.com/cycle-route/marans-la-rochelle), but when we tried to import the whole La Rochelle to Nantes section (https://www.cycling-lavelodyssee.com/itineraire/planifier/1/384/375) only only the first section of the route loads (La Rochelle to Marans). This is the case either through the website, or on Android mobile device. However, we know the GPX file should contain data for the whole La Rochelle to Nantes route, as the whole route from La Rochelle to Nantes loads fine when opened in the Alpinequest app on Android (https://play.google.com/store/apps/details?id=psyberia.alpinequest.full&hl=en-US).