It pretty much moved 1/2 of my lines to using one track, when I had 4 parallel between a number of 4 track stations
I have fixed it again now and they are again running like clockwork, the line they changed to still exists and is in use, although its not designed to handle that many trains 🙂
One spur caused some strange unexpected behavior.  It may well have been something I overlooked, but even so, with waypoints it would have been a non issue 🙂
The main issue was, the lines where all set up working as I wanted, I added a spur, the lines changed.. I removed the spur, the lines remained incorrect and didn’t change back.
I had to bulldoze sections of each track, so as to break the line and rejoin them in some sort of order for it to re-pick / stick with the original intended paths
