Em5 lockup of lens release button. Help needed!

I don't think the length of time matters. i would remove the battery while the camera is off.I would wait a minute or two and reinsert the battery. I would remove the lens and then reattach it and make sure you feel the "click" when it is correctly seated.

I would also suggest you post this on the Micro Four Thirds Forum. There are many more OM D users on that forum and if anyone has had a similar experience you are more likely to get a response there.