Okay, I know that reports to this bug are suspicious. I think I have seen it 2-3 times, but I was never sure that this actually happened, or I wasn't looking close enough. I decided that if I see it clearly once more, I'll open an issue about it.

So, when the ball is moving fast, I mean really fast, after bouncing multiple times, it might fall through a flipper, without colliding. I've seen it happening with this very trajectory twice:

I aim the Hyperspace with the left flipper. I hit the wormhole opener, the ball bounces back to Flags Upgrader (or whatever that is) in a low angle, then bounces downwards to the right bumper. For some reason, the ball is surprisingly fast, and I react late, and I fire the right flipper approximately the same time when it's about to hit the ball. Then the ball just falls without any sorts of collision happening.

I'm using the Full Tilt graphics, if this matters.

I have no idea how to repro this. Probably a carefully set up Demo Game could help. From this time on, when I'm playing on my personal computer, I'll record all my games and hope to catch it..