Twonav Cross Autorouting Next Turn Symbol disappears

I have an new Cross with up to date FW.

Use TomTom DACH Map and start an Navigation Onroad with Autorouting.

At begin everything is nromal. After a while the Top Left Symbol which shows the next Turn changes into the Finish Flag Symbol and shows Distance to Goal.

But Route is navigated normal. If i when leave the planned Route and the Cross recalculate the Route then the Symbol changes again to next turn symbal, for a while.

But after a few turns it changes again to Finish Flag and Distance to Goal.

Is this an known problem or a bug of FW 5.1.1 ?