PDF viewer - view only mode of folder doesn't allow to view PDF into folder


NextCloud version : Nextcloud 18.0.3
Apps : PDF viewer 1.7.0

We have just installed NextCloud to allow users in our company to share files as view-only mode. When I create a public share link on a file by ticking the box “Hide download”, I can share a link and peoples can open the PDF file.
But when I copy the PDF into the folder and I create a public share link on the folder by ticking the box “Hide download”, users can go on the folder and see the files are available but clicking on the PDF brings an error :

The error message says : PDF file missing
Do you have any clue to correct that ?

Same problem here, when i share a public link with “hide download” (but not necessary a folder), pdf doesn’t work : pdf are open with collaboraOnline and its verry blurry.