Expected

Post content is saved when exiting the editor from any view.

Observed

Post content is not saved when exiting the editor from HTML view.

Reproduced

1. Go to Sites tab.
2. Tap Blog Posts item.
3. Tap Create floating button.
4. Tap HTML format button.
5. Enter text.
6. Tap back arrow or back button to exit editing.
7. Tap Edit button on post.
8. Notice no content is saved.

Tested

Google Pixel on Android 7.1.1 with WordPress alpha-33