To reproduce the issue follow the steps:
1. Create a new scene
2. Create a new UI Input Field
3. Set "inputField.contentType = InputField.ContentType.Name" to check for name validation
4. Play scene
First case:
5. While entering text, pressing home button and typing a letter
Second case:
6. While entering text, selecting all (ctrl-a) and then typing any letter

Result: Typed letter is lower case.

Expected behaviour: New typed letter should be upper case.