distanceToDestination inaccurate value

I've built a data field for fun and personal use to get more data on the screen of my Fenix 5x and I was trying to use the distanceToDestination in Activity->Info. I want to have the same data value as the native distance remaining field while following a course. In the simulator this shows the correct data set under the navigation information. However while testing on the Fenix 5x I've noticed that the data it gives is dependent on the Routing setting for the app. If the Routing setting is 'Use Map' the distanceToDestination is accurate but if the Routing setting is 'Follow Course' then it always shows the same distance as the distanceToNext field. I'm using a course built in Garmin Connect to test that has just a few course points to make sure there's differentiation between distanceToNext versus distanceToDestination. Shouldn't the distanceToDestination behave the same regardless of the App Routing option? Is there another way to get the same value as the native distance remaining while following a course?