As so far there is only one reported instance of it out of 2 billion iPhones it’s not clear it is a bug; so far it’s a problem with your phone. There are two ways to communicate with Apple about it: Use the Contact Support link at the top of this page or in the Apple Support app on your phone (or call Apple support: Apple phone contacts) to open a support case. All such calls are logged and maintained in a database, so common problems can be easily identified. The other is https://apple.com/feedback. This is logged also, but it is a one-way communication; you will not get a reply.
There is a 3rd way; register as a developer, and you can then file a bug report, which will be acknowledged and tracked.
Meanwhile, you can try standard troubleshooting steps for Wi-Fi issues:
- If you can, see if the problem occurs with other similar networks; if it is only your own network it may be a router issue
- If you can, try a different phone using the same scenario
- Restart your router - this fixes a lot of Wi-Fi problems
- Settings/General/Reset - Reset network settings - nothing will be lost except Wi-Fi passwords (and “trusted” invalid certificates if you have any, which will have to be approved again)
- Restore iOS to factory settings and test before installing anything, to see if it is a 3rd party app issue or a settings issue. You can restore your backup as a further test.
If you contact Apple support they can run a remote diagnostic on your phone, but they will also want you to try the above steps.
