AS doesn't display 'noitems' message when Admin

When logging for the first time as an administrator, the AS doesn't display any items (as it use to for 4.1 M1 for example) nor the 'noitems' message.

The message is displayed when logged in as a simple user or unregistered.

'noitems' message = "There are no activities in the stream"

The only difference between the 2 users is that the Admin has access to some pages from 'XWiki' space. So I guess this issue is related to the filtering of hidden documents.