Just installed software version 15.5 and installed a .TCX route downloaded from RidewithGPS.
On my ride it was NOT showing directions prior to a turn at all but did sometimes show the next road name with an arrow for the turn in a very small font at the bottom of the screen. (I had the screen up with the speed, heartrate, cadence, temp, etc)
It used to come up on the entire screen with the map turn etc prior to the turns.
This does not work for me and seems like there is something wrong with this update on the older G1000.
-Don in Seattle