There was one very amusing bug. The author had clearly put huge effort into building a polished interface, but then added a new button at the last minute. That button is available if you have a flag right next to a straight road. If you pressed it, then the road would be cut in two and both cut ends attached to the flag. It would otherwise save a load of time clicking round destroying the road and rebuilding it.

The bug was that the game didn't check that the road was yours. So, if an enemy had a road running along their border, you could place a flag right next to it on your side of the border, then click the button, and you'd have a new road crossing the border, and the two independent road systems would be connected. And because all the goods were fungible and distributed on a supply/demand basis, your enemy could start supplying you stuff.