I found two plunger bugs that are probably related. I've seen the bugs across all tables, but they are easiest to reproduce on Big Shot, because you get 5 balls, it drains easy, and there is a long trough for the ball to travel up and back down.
Bug 1
Plunge gently, enough for the ball to move, but not enough for it to clear the gate at the top of the pathway. The ball will fall back down, ready for another plunge. Plunge gently again so as to move the ball but not hard enough to clear the gate. While the ball is in motion, pull and hold the plunger back. Wait for the falling ball to return while still holding the plunger back. When the ball stops moving, go ahead and release the plunger. The ball will jiggle when the plunger strikes it, but it won't travel up as expected for some reason. Once the ball is motionless again after the jiggle, you can plunge and the ball will react normally and travel upwards.
Bug 2
Plunge gently (so as to make ball go up and come back down), release plunger, watch ball travel up, stop, and start rolling back down. While the ball is traveling down (but before it reaches the plunger), pull back the plunger and release. The ball will react as if struck by the plunger (which if hasn't reached yet) and fly upwards. The crucial part is plunging while the ball is falling downwards. If you plunge carefully enough, you can keep dribbling the ball in the trough.
Bug 1 is like the ball won't fly upwards on a plunge until it has touched the plunger at least one time beforehand.
Bug 2 is like the ball will fly upwards on a plunge it hasn't even touched yet.
This is in the Android app, and has been there for the last few versions.
Bug 1
Plunge gently, enough for the ball to move, but not enough for it to clear the gate at the top of the pathway. The ball will fall back down, ready for another plunge. Plunge gently again so as to move the ball but not hard enough to clear the gate. While the ball is in motion, pull and hold the plunger back. Wait for the falling ball to return while still holding the plunger back. When the ball stops moving, go ahead and release the plunger. The ball will jiggle when the plunger strikes it, but it won't travel up as expected for some reason. Once the ball is motionless again after the jiggle, you can plunge and the ball will react normally and travel upwards.
Bug 2
Plunge gently (so as to make ball go up and come back down), release plunger, watch ball travel up, stop, and start rolling back down. While the ball is traveling down (but before it reaches the plunger), pull back the plunger and release. The ball will react as if struck by the plunger (which if hasn't reached yet) and fly upwards. The crucial part is plunging while the ball is falling downwards. If you plunge carefully enough, you can keep dribbling the ball in the trough.
Bug 1 is like the ball won't fly upwards on a plunge until it has touched the plunger at least one time beforehand.
Bug 2 is like the ball will fly upwards on a plunge it hasn't even touched yet.
This is in the Android app, and has been there for the last few versions.