Thank you, that did the trick! I found approx. 20 pages throughout the site with images set to full width and fixed them. The interesting this is, looking at the revision history of those pages, I find that the most recent changes to those pages were from on average 6 months ago, and they all had the full width setting turned on since then.
Have there been an changes or fixes to that piece of he framework’s functionality since then, that would cause it to start behaving “as intended”, as soon as it got updated? I need to be able to explain to the client how this even happened in the first place.
Thanks again for your help!