Additional note for Android borderRadius clipping #3198

docs/KnownIssues.md

@@ -67,6 +67,8 @@ There is currently no easy way of publishing custom native modules on Android. S
 
 This is a result of how Android rendering works. This feature is not being worked on as it would be a significant undertaking and there are many more important tasks. 
 
+Another issue with `overflow: 'hidden'` on Android: a view is not clipped by the parent's `borderRadius` even if the parent has `overflow: 'hidden'` enabled – the corners of the inner view will be visible outside of the rounded corners. This is only on Android; it works as expected on iOS. See a [demo of the bug](https://rnplay.org/apps/BlGjdQ) and the [corresponding issue](https://github.com/facebook/react-native/issues/3198).
+
 ### No support for shadows on Android
 
 We don't support shadows on Android currently. These are notoriously hard to implement as they require drawing outside of a view's bounds and Android's invalidation logic has a hard time with that. A possible solution is to use [elevation](https://developer.android.com/training/material/shadows-clipping.html), but more experimentation will be required.