When trying to upload new volumes to Panels I noticed something peculiar: as per the attached screenshot (taken in infinite scroll mode, a video would have been better to demonstrate what is happening), panels would display the exact same page over and over again when I tried to open it in Panels.
Due to the nature of these repeating panels, I have deduced that it likely has something to do with sub-folders in the .zip/.rar file that became a .cbz/.cbr file, since I found that in this particular volume there were seven repeating images and seven chapters in the volume. Additionally, when I tried uploading a version of the volume that had no sub-folders the volume turned out as it was meant to, there were no repeating pages.
I’ve used .cbz/.cbr files with plenty of sub-folders in the past, and they have worked just fine. In fact, these .cbz/.cbr files with sub-folders continue to work as they should in Panels, so I suspect that it has something to do with the nature of the upload process in a recent update or something.