There is code in place to respawn the ball if we detect that it's stuck inside a block or wall, which can occur due to frame drops during the physics simulation. I'll try to reproduce this issue. Thanks for reporting it!
I was being malicious and dropped down onto the hovering pink cube outside the play area on the final level. Once you roll off that pink cube your respawn point is on the cube, leaving you stuck and unable to get back to the main course.
NBD but sharing in case you want this kind of playtesting feedback!
NBD but sharing in case you want this kind of playtesting feedback!