Hello i have experienced some issues with the smart key when i put it with my cell phone in the same pocket. My door wont open when i hold the handle or wont close when i press the button on the handle....
This is noted in the owners' manual as a source of potential interference. Keep the two in separate pockets and it'll be better.
Also a good idea to keep in separate pockets, anyway, if you have any other keys on the same ring. Keys have a tendency to scratch phone screens.