Hope you all are doing well.
I'm having this issue after MOODLE upgrade from 3.10.4 to 3.11.1 that Annotate PDF and Feedback Files under Assignment\View All Submission screen is giving us forever spinning wheel. Now when we are going to student's individual grading screen through check mark on Grade Me block, Annotate PDF editor and Feedback Files area is working perfectly fine.
Checked the UNOCONV, LIBREOFFICE, GS, PATHS, PLUGINS, SERVICES and tested CLI conversion, rebooted after upgrade and what not.. lol! Not sure what's wrong with that View All Submission page. Please help us resolve this issue!