I sent in a support email on this issue 6 days ago, but haven't gotten any response yet...
After updating my iPhone to iOS 8 and 1Password to version 5, I can no longer enter Notes for an item. I am currently running iOS 8.0.2 on my iPhone 5s, with the latest version of 1P.
I'm not sure if the problem is the new predictive text buttons or something else, but any notes more than about 1 line are hard (or impossible) to view and/or edit when entering/editing the notes. This is a real inconvenience and needs to be fixed quickly. It will likely affect users on ALL iPhone models running iOS 8. Even some users of the iPhone 6 and 6 Plus will be affected, as many will choose to run Display Zoom.
I look forward to hearing from someone on this. Thanks, Scott