I’ve tested this in xWiki 10.11.9 and 11.10.2.
When using the Notifications macro or the Activity (legacy) macro I cannot limit the displayed activity to a page and its sub-pages. The macros seem to ignore my pages parameter such as:
No matter what I enter, I get the activity from everything in the wiki. This used to work as expected for me in xWiki versions 9.x using the old Activity macro.