Neither vo-f2-f2, nor vo-f1-f1, report the number of windows or apps open. Vo-f1 reports "[app name], x running applications", which is good. However, vo-f2 does not, and there's never any announcement of how many windows are open. This is with verbosity on high.
Bug First Encountered
How often the bug occurs
Pressing VO f1 f1 and VO f2 f2 now announces the number of open apps and windows as expected.
Also on Sierra, I'm still seeing vo-f2 fail to report the number of open windows.