Hi Gary, this looks to be an issue that Articulate will have to address. Looking at how it handles reading order, it adds elements to an HTML container with the class name "acc-shadow-dom". It does not add webobject, or embeded videos to this container, and therefore they are always read last.
This seems like it might be a bug that has been introduced as I'm sure I have used webobjects and embeded videos in the past and been able to set the correct reading focus, but I can see from the current HTML output, this is not going to be possible.
I attempted to do some manipulation with JavaScript by moving the video into the "acc-shadow-dom" container, but this is not an easy fix as the size and position of the video was changed due to a scaling property on the "acc-shadow-dom" container.
I have reported this as a bug to Articulate. Case number 00831827