I have found a working solution to the error where you have *previously uploaded a geojson*, but then removed it in the dashboard because you don't need it anymore, because your app binary does not use routing and therefore does not have the MKDirections* properties in the app's plist-file:
Remove the routing file
Save
Add the routing file (now, be quick for the next step)
When the upload happens, there is a small "Delete" link next to the upload field. Press it before the upload happens
Save
If you were too slow to perform the step 4 after the step 3, just restart from the beginning at step 1.
The trick is that there seems to be a difference in the "Delete" link briefly displayed and the "Remove" button once it is uploaded.
Folks, good luck in releasing your app!