@Rob-Veerman Hi Rob,
The HERE-map version in web and Navigation may differ for any number of reason, but as people correctly guessed already in this thread, this is by no means our (MRA) intention. Maintenance on these maps is done by HERE, not by MyRoute-app. Both Navigation and MRA Web use what's called an API key which facilitates the communication between HERE's map database and the different MyRoute-app services.
To create a visual metaphor: imagine that instead of a routeplanner, MRA delivers you each day two boxes of apples. One day you open both boxes and find that one box (MRA Navigation) is empty whilst the other still has apples. This is what happened here, one service (WEB) has an updated version of the map you're looking for while the other service (Navigation) apparantly doesn't have the version you're looking for. We both don't expect this but it does happen occasionally. The reason for this is as good a guess for you as for us. The missing apples are not something we could have known about, since the orchard (HERE) gives us the boxes. Hopefully this answers your question as to how this could happen.
Next question: why does MRA not report this to HERE? we do, however it does take some time for a specific question like this to get on our radar. To go back to the example of apples in boxes: when we send out the boxes we can't check every single box, instead the orchard promises to check them for us and correct it if something goes wrong.
Now your final question: how come your Zumo does show the right route? This may have several reasons, but the most logical one that comes to mind is that the map on this Zumo isn't up to date. Again, this is pure speculation, but if all permantently connected services (Navigation, MRA Web and even Basecamp) show the exact same behavior, then it's most likely that this is the case. To go back once more to the example of apples: your Garmin XT might as well be an old box of old apples, there's no correlation between that box and the boxes you received today.
I hope I've been as clear as possible. Thank you for your time.
Kind regards,
Timo