Can't upload iCloud images form linekd album

Now this is quirky: I have many iCloud shared albums, a mix of my own that I have shared to others and some that others have shared to me. However, there is one specific shared album where trying to add a batch of photos into the Meural playlist fails with a message "some items failed to upload" - on investigation, none of them uploaded. Repeating for just a single photo also fails. Adding a single or multiple photos from any other shared iCloud album or my own non shared photos in iCloud works fine, so there is no image limit in my Meural playlist that I have reached and hitting. I tried restarting the Meural app, but get the same error. Looks like a bug with the iCloud shared album - so I'll ask the other family member to re-share it to me and see if that works, if not, then I will check the source image properties in that shared album in case there's a bug with Meural's support for different file formats.