Apple watch 3 keeps rebooting and turn on only while connected to charge

Requesting for your help. My Apple Watch 3 works quite well, except one moment - if you decide to turn them off - they won't turn on after, regardless of battery percentage. They proceed with endless rebooting - Apple logo appears, then black screen, pause, some seconds, again Apple logo and so on. They only turns on if you connect them to charge, then after rebooting they start normally and you can go ahead. I guess they shouldn't work like that and you should be able to turn off them when you need

I face it for the 3rd time within half a year and software updates didn't solved the issue. Hard reset is also useless. Any ideas?