Yes, at the end of the day, characters wander all over the place from where you initially point them. They eventually come back to where you pointed them at the end of the day, but you'd be surprised where they have to ricochet off of to get where you want them to go.
Heck, when I was doing Honor At Stake, I've still got those issues. I had cops and mobsters showing up, when they were never in the book -- not that they weren't planned to take on as big a role as they did, I mean that they were never in the book in the first place. I had a cop appear at one point because I needed someone to deliver information. He was to never darken my plot ever again. He wasn't going to be there, period.
By book three, he's got a subplot.
Hell, there is also a mobsters known simply as Enrico, who I based off of Michael Rennie, of The Day the Earth Stood Still, and he was only there so there could be just another bump in the rode. Nope. Nothing more. Nothing less. Just a thing that happens.
Now he's becoming a major player over time. Yeesh.
The fictional people are still taking over my life.