Power Button stopped working properly

Hello, my power button stopped functioning properly after my device lost connection with my phone several times. Since then my power button doesn't react when pressed. However, long press works 50% of the time, so I can turn it on/off, but I can't double press the button to open an app or turn off the screen for instance. It's really strange. I haven't dropped or physically damaged the watch. I tried hard resetting it 3 times, but that didn't fix the issue. Everything on the watch works apart from the power button. The phone charges perfectly. Any ideas? Do you think this could be caused by a software or mechanical thing?

Any suggestion would be appreciated.