Error: Apple watch wrong passcode/lock out

This has happened a couple of times. I wasn't wearing my watch and I notice the apple symbol on my watch screen while it's sitting on my desk. The buttons aren't being pushed or up against anything. When I pick it up and press either button the apple symbol goes away then comes back. After 2 or 3 times my normal watch screen comes back but then say wrong passcode wait 4 minutes. Why is this happening if I'm not wearing it or trying to put in my passcode?