Apologies for the delayed reply and my misinterpretation of the issue I have presented above.
To be clear, upon further analysis, the above functionality is the intended design and there are no bugs present in what I presented.
So what happened then?
The reason that a background image seemed to appear after adding in a category logo image is because in the “about this category” topic I had placed the same image that kept appearing in the top of the topic.
I had mentioned this above and I’m glad I did add in that detail. It’s just unfortunate I didn’t put two and two together sooner.
Whenever I added a category logo image, the image in the top of the “about this category” topic would also appear due to how the Discourse category summary feature works in conjunction with the application of a category logo image. When a category logo image is not applied to the category, the “about this category” topic no longer gets summarized, thus the misidentified ‘background image’ disappears too.
So, if that jumble of words made little to no sense…
Logo image applied to category + image at the top of a “about this category” topic = summarization of “about this category” topic.
Result: That image is summarized in its full size and glory. To me, while this is intended functionality, it shouldn’t be. But I’ll save that for another topic.
Moving the image in the “about this category” topic toward the bottom means it no longer gets summarized and no longer appears in that section, just in the topic itself.
Again, I apologize for wasting anyone’s time investigating this non issue.