Is this a bug, or were there problems with the feed of data. DL77 on June 16th, seems to waltz all over the N.E, before deciding to jump back to the Atlantic south of Newfoundland. Then the track stops at 14:42 EDT, although the flight did not arrive at KATL until 18:00 
BTW the Delta.com flight tracking showed the same mixed route over the NE, but did not stop tracking at 14:42.
Stefan
The zig zag back to the mid-atlantic is due to a bad position report, but the overland track is also curious. It could have been another Delta flight ending in 77 that was mistyped while DAL77 was over the Atlantic. Or just gremlins.
The tracklog and map is now complete; there is a bug that is making some tracks stop early while the flight is in-flight, but it’s corrected after the flight lands.
In the future please note the map server number (right click on the map and choose Properties) when reporting a map anomaly.
Thanks for the quick reply, just out of interest, have you looked at the remaining track, after 14:42. For a while it looks OK, then there seems to be a problem with the flight levels/altitude with major differences within the minute. More gremlins? 
Looks like the usual nonsense, with another radar station reporting the aircraft at the assigned altitude (either cruise or intermediate during a climb/descent).