It is a bug and very annoyed. I have a forest supplying logs to two saw mill. On terminal 1 there are two trains and on terminal 2 two trains identical to the ones on terminal 1. The problem is that terminal 2 gets 99% of the logs and terminal 1 very few. In another part of the map I observe the same problem from the steel mill, one terminal gets most of the steel while the other terminal starves.
Have you had the same problem? any solution?