We discovered that these two values crash the app on Android. I found that it happens because of bad case-statement that looks like this:

case VerticalAlignment.center || VerticalAlignment.middle:

The default case picks up everything that doesn't match and raises an error for an unrecognized option.

Affected files:

• ui/core/view.android.ts
• ui/core/view-common.ts
• ui/layouts/stack-layout/stack-layout.ios.ts

I'm submitting PR to resolve this in a minute.