Please be aware that Microsoft Windows got an update KB5003637, which breaks FileMaker displaying PDFs in an interactive container.
You may want to not install this update for some time or uninstall it when you find it installed.
An upcoming FileMaker release may switch to use Edge/Chrome for rendering PDF documents, so this will get fixed soon by Claris.
See also posting in Claris Community: Suddenly PDF are not shown in FileMaker (since today !) in multiple computer / different customer