Detailed and Effective Bug Reporting

For more complex/tricky to reproduce issues or issues that have been confirmed as being real issues for multiple people.... for which no solution has been found...

I've found reporting via the Apple Bug Reporter functionality to be even better that using the feedback form.... as you, the reporter of the bug, can easily track any responses from the Dev team... and very occasionally, even feedback on any work being done on this particular bug report made by you or others..

https://bugreport.apple.com

Note: You must first create a free Apple Developer Account to then be able to use the Bug Report functionality.... but it's well worth it I've found..

https://developer.apple.com/register/index.action