This is a native Affinity Publisher document. I am fuzzy on exactly what I did, as I wasn't expecting trouble and I have been fighting with this for a few days now. I was asked to replace the two images that were on the left-hand page. The new images had some cropping, but I wanted to keep the existing layout. I placed a new image over the existing image in the top frame, and replaced the text for its caption. Those are ok. I have forgotten what exactly went sideways with the lower image and caption, but I ended up deleting them and drawing new frames. I was able to type the word "caption" into the new text frame, but it has since become uneditable, and I can't place an image or do anything else with the new image frame. These are (caption) and (Picture Frame) in the layers panel.
I'm not quite sure how to approach getting just the problem page into a new Publisher doc. This is a book, and the text in the (Carol J. Bornstein... layers is flowed through nearly all of the document, with pinned content throughout. I imagine the sending the flowed/pinned content crashing through would obfuscate things. All of the other text layers come from the master page.