Spindle grinds into the paddle...

This is one of the most common troubleshooting issues with the Ninja Creami.

Sometimes the paddle disconnects from the spindle when the ice cream is processing. The paddle is connected to the spindle with a tiny magnet. If the paddles gets off center or knocked loose from the spindle while processing, for any reason, the spindle can drill down into the paddle.

There are various reasons that this can happen, none that have been confirmed by the manufacturer.

The spindle is no longer perfectly straight which causes the paddle to process the ice cream at a slight angle. When this happens, the spindle can start to drill into the paddle.
The paddle is not attached to the spindle 100% correctly (magnet may no longer be strong enough to hold the paddle on correctly).
If the top of the frozen mixture is not level, it could cause the paddle to be off balance, causing the paddle to detach from the spindle. When this happens, the spindle can start to drill into the paddle.
Wrong ingredients or wrong temperature of mixture is being used which causes the machine to struggle and go out of balance, causing the blade to detach and the paddle to grind into it.

How to resolve the issue...

When this happens, it's usually a bigger issue with the entire machine.

Do not buy new paddles as it's possible and quite likely that it will continue to happen and get worse.
Do not continue to use the machine. If you continue to use the machine, the following can happen.

The paddle can get damaged.
The spindle can get damaged and bent.
The magnet that connects the spindle to the paddle can get damaged.
The motor can get damaged and can cause the machine to overheat, smoke, or start on fire.
The containers can get scraped.

You need to contact Ninja directly to resolve this issue.

Contact Ninja through their customer service phone number.

Warranty number: 1-866-826-6941

Customer Service US: 1-800-365-0135