XWiki doesn't check groups permissions correctly in multiwiki environment

I have one user on main xwiki that watches all changes on a subwiki and on main wiki. The XWiki.Admin user also watches all events on main wiki and subwiki. I change Sandbox on main wiki and Sandbox on subwiki. Then I go to Scheduler and trigger hourly job.

The XWiki.Admin user receives a notification on both events while the other user only gets notification on event on main wiki.

I switched the xwiki-plugin-watchlist.jar with another one that prints a lot of debug info. The new JAR prints the list of raw events that WatchListEventMatcher gets in its constructor and the lists of matches events per subscriber in getMatchingEvents.

I observed that both events were processed but for the user the event on subwiki was discarded. After a few more debugging I discovered that the event was discarded because permission by the check context.getWiki().getRightService().hasAccessLevel("view", userName, event.getPrefixedFullName(), context). I enabled log for right service and got access denied messages to resource because "(restricting right was found)".

The I double checked permissions for that user. Only if I grant "view" permissions for user on the page the event gets added to matching list.