Magic interferes with how electricity or electronic devices work. How bad it gets depends on how complex something is and the amount of magic we're tossing around
Magic can permanently damage some devices too. A friend of mine once said it's like an extreme case of Murphy's law. We used to cause dairy products to spoil and warts and boils to appear on human skin too
I guess it's all about balance. And emotions. Humans are messy and it can make magic messy