You may notice that the game asks you to spend gems to buy PowerUps when the power bar is full. Actually this is no bug or glitch. It's because you only have a few kinds of PowerUps.

Here's the reason why the PowerUp system is designed in this way: We want to offer players different gameplay experience, so a random PowerUp pops up when the power bar is full. It may not be the PowerUp in your inventory.
Besides, you can increase your chance of getting bingos by using different kinds of PowerUps!

If you have further concerns or any suggestions, feel free to contact our Support Team.