Bummer this has been around so long with no reply. Surely it happens to a LOT of people. Replying mostly to subscribe.
One thing I’ve noticed, while previewing in the FB “Pages” app, is that even when this error DOESN’T show I get erratic behavior WRT the “Cover Image” and “First Image”.
I DONT USUALLY SEE THE ERROR DISCUSSED ABOVE
I have Cover/First Image using sufficiently similar formats that I usually don’t see the error. My featured image size is a 16:9 crop of upload, my “large” size is original aspect ratio and often close in size/shape to the 16:9 version as long as the image is “landscape” orientation.
I see the error for posts with an image inserted as “small” size at the top of the post.
FB IA IS CHOOSING WHICH ONE TO SHOW WHEN THEY ARE THE SAME
On some posts, the result is iA hides the “Cover Image” completely and the article starts with the site logo and post title, then the post content including image.
On other posts the Cover Image is shown and (WTF) the image in the post is completely hidden, including it’s caption.
It seems like FB has some logic that, WHEN THE ERROR DISCUSSED IN THIS THREAD IS NOT SHOWN, but it detects that the images are THE SAME, it hides one of them or the other to avoid total duplication.
My question is WTF is that logic and how can we predict which will happen?
For me, I’d much rather keep the in-post image rather than the cover one, because it usually has a caption with attribution information/links that are legally mandatory (Creative Commons). Replacing it with the Cover Image means only the pic is shown, and so far I’m not seeing any evidence of it copying the caption into the caption field of the Cover Image.