What version did you upgrade from? The field you are seeing is the “figure attachment” field. It holds one file and many of us used that as a convenient place to save a PDF before they added the File attachment field (circa EndnoteX?) which can hold multiple files. If all you ever used the fig attachment for was PDFs and never to hold Figures to use the relatively useless insert fig option, there is a convenient transfer you just need to use once. Under References>figure, there is a conversion utility. Open your library, select all and perform the function conversion. Then change your display (from Preferences) to show the file attachments rather than figure field in the first column, and it will look just like it used to, but with the ability to attach multiple files (say the PDF and the supplemental files).