Unable to share a video if "optimize for video sharing" is enabled

Hello, I've been using Zoom for a couple of years now conducting meetings with up to a few hundred participants.  The presentation always includes the sharing of a video.  I have always used the Share Sound and Optimize for video settings.  A few days ago, while doing the AV check in preparation for the meeting, I was unable to share the video.  The participants were able to hear the sound but unable to view the video.  In an attempt to resolve this issue, I have replicated the issue with a small meeting between two of my own computers, one desktop (with a hardwired ethernet connection) and an iPad (connected with WIFI).  I have also replicated the issue with two computers both of which were connected with WIFI (i.e., no hardwired connection).   The issue began with upgrade 6.4.2 and persists with 6.4.3.  I can workaround this issue by disabling the "optimize for video sharing" feature.  Any thoughts on how I may resolve this?