In the hopes the developers review this forum to improve Basecamp Id like to offer an issue I have observed.
If one converts a track to a route in order to be able to modify the route, say by rubberbanding the original route to new desired paths, the entire route will collapse between the original start and the new point added during rubber banding.
See the attached graphic that illustrates the before and after after a single change was made use the Alt/mouse left button.
The only workaround is to keep the original track, display it on the map and draw your new modified route over the top of the track using the track as guide.