One more thing I thought of was that with the latest plug-in you can select self-hosted. If selected you can/should change the url of the video, and/or the embed code. There are some complexities I haven’t figured out, but on my site, I am using the code that Sam suggested for me in this thread. https://s3bubble.com/forums/topic/self-hosting-setup-issues/
Look down into the thread and notice this<div id="s3bubble-unique-id" class="s3bubble" data-setup='{"codes": ["WefX43476"]}'></div>
I think this is down to the specific way you are building your WordPress posts, but you might try to update the embeds like this and see if it helps. I changed all of my embeds to this scheme and I am getting much faster page loads with no errors.
Grace
VFC