Steps to reproduce:

Visit:
https://www.w3.org/WAI/tutorials/forms/notifications/#during-typing

and type in the first field under the heading "Approach 2: During typing".

Actual behavior:

OK is announced after every key press, no matter how fast the user types.

Expected behavior:

From the description of the example:
"The value “polite” de-emphasizes the importance of the message and does not cause screen readers to interrupt their current tasks to read aloud this message. Thus the message is only read once when the user stops typing rather than on every keystroke that the user makes."

System configuration:

NVDA Installed/portable/running from source:

Installed

NVDA version:

Version: 2018.3.2

Windows version:

Windows 10 64 Pro

Name and version of other software in use when reproducing the issue:

Firefox:
63.0.1 (64-bit)

Have you tried any other versions of NVDA?

no