Thank you Kirk. I loaded up the v4.6.7 beta - no difference therefore still no watermark. The screenshot is attached and unaltered from when it was working well prior to v4.6.6
Are you certain that your images contain data in the Copyright field of their IPTC metadata?
If so, what happens if you change some of the Watermark settings like: position, size, font or color?
What about if you tell it to render your overlay image? Does it show up?
-Kirk