I'm seeing references to this issue online, just posting my experience. I have a newly purchased iPhone 8, which came with 11.0 installed. On one occasion, the lock screen froze, and the phone was unresponsive to the home button and the volume buttons. Pressing the on/off button rendered the phone responsive again. I have upgraded that same phone to 11.0.2. The lock screen freeze just happened again this morning. Again, pressing the on/off button renders the phone responsive. I found the article to which I am including a link, which has me feeling relieved (that it is not a hardware issue related to the home button). The article indicates it is Apple's software problem. I have submitted a bug report to Apple.
https://www.forbes.com/sites/gordon...-problems-bluetooth-performance/#206611445d95
https://www.forbes.com/sites/gordon...-problems-bluetooth-performance/#206611445d95