Diagnosis
The membrane behind the touch panel is failing or has moisture/grease contamination.
How to Fix It
Unplug the unit. Clean the control panel with a slightly damp cloth and mild soap. Dry completely. Use a dry cotton swab to clean around the edges of each button icon. Grease can create a conductive bridge causing false presses.
If That Didn't Work
The issue is internal. The touch panel is integrated with the main control board. There is no user-serviceable fix. Contact Ninja support. They may offer a control panel overlay or board replacement under warranty.
Heads Up
Do not use glass cleaner or abrasive cleaners on the touchscreen. It can damage the coating. Avoid spraying liquids directly on the control panel. Wipe spills immediately.