Re: strange behavior with Microsoft sapi 5 voices and NVDA
Ladies & Gentlemen, why not avail yourselves of Microsoft Windows & Office Accessibility Support? U.S. Toll Free: (800) 936-5900
US Microsoft & Windows Accessibility Support Webpage
UK Microsoft & Windows Accessibility Support Webpage
When you can go to the source, or close to it, at no cost it makes sense to at least give it a try. Even more so when the issue crosses products, which, as you've already noted, suggests the issue is on Microsoft's end.
Brian - Windows 10 Pro, 64-Bit, Version 1909, Build 18363
Power is being told you're not loved and not being destroyed by it.