I was testing my AI, when suddenly the game crashed with a message "Disconnecting road vehicle". To reproduce the crash: the savegame (and the crash dump file) can be download from this forumpage. The AI, RailwAI version 7, is available via the in-game content downloader (BaNaNaS). Crash occurred on the in-game date 2000, August 7th (1½ in-game years after the savegame start).
Sorry, I can't reproduce the error. I tried using 1.8.0, downloading missing NewGRFs from BaNaNaS, as well as RailwAI from BaNaNaS too, and let the savegame run until 2000-08-07 (looking around the map and at the AI debug window, but not building/changing anything) and nothing happened on the date.
Weird bug indeed. Yesterday, I was able to reproduce the crash by running the savegame again. Now, I'm not able to reproduce the crash either. I see in the AI debug that multiple AI instances are busy with building and removing roads. Also, a few AI are telling some road vehicles to skip a few orders in the order list. I don't know what could cause the message "disconnecting road vehicle".
There's only one place in the code that can produce the message, and it's when the FollowPreviousRoadVehicle function fails for a road vehicle trailer.
I think one possible case is if a bridge, tunnel, or depot is deleted the tick after a road vehicle has left it. Possibly also if the road is changed on a tile after the truck has left that tile but the trailer hasn't yet.
Thanks for this. At the time of writing this appears to be an isolated bug, and hard to reproduce. We do try to address bugs where they occur frequently and/or are easy to reproduce, but this one doesn't look like we can any go further, so I'm closing it. Thanks for contributing!