I just tested it and I don't seem to have that issue... Have you changed anything before this happened? The current 2.5 version should be fully compatible with the latest version of Game Maker Studio.
Sorry, meant the default room. I'm loading the default room after copying everything to a new project, and the ball just won't leave the plunger lane. Debug shows it hitting a spot at the exit that isn't a wall. Do objects in the title room need to be loaded previously as well? Haven't changed the default room at all, just imported everything to a new project, and attempting to use my own title room, and then loading the rm_default.
The default room works for me as well (but I havent tried exporting the whole project into another one).
The default room is basically a pinball table stripped of everything, just flippers, plunger, ball, ... as a nice starting point.
Does the ball not launch, or does it go up but hits something invisible so that it can't exit?
At the end of the plunger lane is a single-pass-through invisible wall capsule. It is used so that when the ball does exit the plunger lane, it can no longer go back inside during gameplay. It's possible there might be something going on there, but I think I need a bit more details since it works on my end.
Good to hear you solved it, and I'm glad to be of help!
I am going to update this again when I have the time, primarily due to a small mistake I made (but also because I have more ideas for cool stuff to add).
If you scroll through the comments here you'll see the solution to it however. In the current version, it's not really possible to add a bunch of extra friction on the flippers, due to a line of code being misplaced. I have typed the solution in this comment section in one of the replies :)