When I'm driving my car and step on the brake, the touchscreen on my 2015 mazda 3 starts moving randomly. It will move between bluetooth, radio, messages, etc. Does anybody else have this issue? Any ideas on what it could be?

 

Sounds like the "Ghost Touch" issue that Mazda has identified. If it is, I believe they extended the warranty to 7 years to fix it for you. Call your Mazda Dealer.