Running iOS 11.0.3 (mmost current for mine I suppose) on an iPhone 6. Works fine (and has the "forget" buttons on each line in smart home scenes)...
I know this is of no help to the conversation, but I've noticed the iOS 11 has some glitches. My company uses a web based Time management system for payroll and robbery of it's employees... (Trust me it skews HEAVILY in their favor)... Everyone in the building can sign on using their mobile device... iPhones and Android alike. I don't even have the option on my App... using the same app version as he person next to me... the Punch option for clocking in/out is flat out missing on mine. Completely weird stuff.
I suspect this is the kind of thing you're having issue with. It probably has something to do with a totally unrelated App that uses a single piece of hardware in the phone, such as Geofencing may be the issue on mine, since their app uses geofencing, and I have another app that uses it also... They don't want you clocking in from home. The Smart Tstat I have allows me to set up and use Location distance and all to control certain aspects of my Air conditioning system.