A few days ago, I uploaded a pdf on Zotero from my ipad, and it stayed there as an item without a parent item. Today, I imported the article corresponding to this publication (https://proceedings.mlr.press/v178/ding22a.html) into Zotero on my desktop, using the Firefox extension button.
On my desktop, I could then see the pdf with no parent (which Zotero couldn't locate, supposedly because it's only on my ipad), and the newly imported item (with full PDF).
I then dragged the parentless pdf into the new item, meaning that this item now had two pdfs, one accessible, and one inaccessible.
Then, I saw the item appear on my ipad, so I clicked on the Info icon to look at the two pdfs in this item. But, the app crashed.
If I try with any other item, it works, it's just this one, which makes me think it's related to the weird procedure I did before.
At this point, syncing on the ipad said "Finished sync (1 issue)", and when I click on it, it says:
"Invalid propery 'pageIndex'
Invalid propery 'pageIndex'
Invalid propery 'pageIndex'"

I then completely deleted this item and its pdfs (also from Trash) and synced my desktop and my ipad. I still got the 1 issue when syncing on the ipad, but everything was fine on desktop.

Then, I re-imported the item from Firefox (link above), but again, Zotero iOS crashes when I click on the Info icon of that item, and not for any other ones. But on the ipad, I'm able to click on the item, and it downloads the pdf and displays it fine. It's really just clicking the Info button that makes it crash.

The crash report ID is 658228825.

Thank you for your help.