Which target are you seeing this issue on? Are you able to reproduce the issue with just the code below, or could it be because of some other code in your project?
We use the native text editors for each platform, PlaceholderText and PlaceholderColor are properties that are not natively supported on all platforms (for example UITextView does not support it on iOS). We have decided to remove these properties from <TextView />.
Also, making a placeholder is very easy in UX (also a reason for not creating a hack instead of removing the feature).