This is a bug that we are currently working on. The newest release has put in place several bug fixes around this issue. However, it is not a retroactive fix, so you may need to retrain SwiftKey Keyboard by following the below steps:
- Long press the word in the prediction bar
- Select ‘do not predict again'
- Tap on the correct lowercase version
While the cursor is touching any word, you have the option to tap ‘shift’ to cycle through different caps cases, Title Case, ALL CAPS, and lowercase. This will help you fix the word without having to re-type it.