k, … I eventually figured out that if I switched the thumbnail at the youtube site and saved the video, then reloaded the wordpress site the image refreshed, and then I could change it back to the previous image and refresh again and it’s now the correct image.
Still though, seems like this should be fixable … by looking at the previous forum posting asking the same question I’m not the first to run into this and doesn’t seem like they figured out the thumbnail trick on the older thread.