1. Open the Windows 10 Mail App.
2. Compose a message.
3. Make an error or force the use of backspace in any field (To, Subject, etc.)
   Expected: NVDA announces the character that is removed.
   Actual: NVDA announces absolutely nothing.

NVDA version: master-14241,57432f41, but noticed with NVDA 2017.2 as well.
Windows version: Windoes 10 1703 (OS Build 15063.483, but noticed with other variants of Windows 10 Creator)

Narrator does not have this issue.