Pdf uploaded files marked as duplicates erroneously

I’m trying out paperpile and am running into an issue where when I upload multiple PDFs, if they are from the same journal, sometimes it labels them as duplicates and concatenates them. I’ve tried deleting them and uploading them again. Also, adding them each individually from google scholar. That works at first but it still thinks they are duplicates. See screenshot where the files are dif sizes.

Does anyone know what might be going on here? If I can’t resolve this I will try a different reference manager. Thanks.

Thanks for reaching out via chat as well about this issue, @jsm - glad we were able to sort things out there.