See the following savegame:
https://dl.dropboxusercontent.com/u/61716/longblock.rar (https://dl.dropboxusercontent.com/u/61716/longblock.rar)
The convoy in the frame is scheduled to stop at Lowdham and then Carlton before Nottingham. It stops at Lowdham and then encounters the long block signal, whereupon it reserves a long section of track. Its destination is now listed as Carlton. But when it reaches Carlton, it goes through the station without stopping, and once it passes the station its destination changes to Nottingham.
Taking out the long block signal (and replacing it with an ordinary one) removes the behaviour, so the long block signal is definitely the culprit.
Thank you - found and fixed on the 11.x branch.
Thank you! :)