Not able to maintain attachement for a PR at item level

No, this is not supported extracurricular the Fiori App scenery - 

For the My Inbox / Workflow processes, you should *not* beryllium processing / releasing documents extracurricular the Fiori App, specified arsenic successful the bequest / older transactions ME5*N / ME2*N, the processing should beryllium kept astatine the app broadside only, to guarantee the consistency of the procurement processes;

Published KBAs / Notes for ME52N / ME53N bash let attachments, but arsenic PRs are draught documents these won't nexus to / beryllium disposable successful the My Inbox and Workflow Apps;

To guarantee the strategy works correctly, delight lone usage Apps oregon backend (not some together).

Hope this helps!