Ratings average is not updated if the ratings are installed on multiple wikis

How to reproduce:

• on a wiki, install the ratings application on the main wiki
• [create a subwiki]
• install the ratings application on the subwiki
• back on the main wiki:
  • using the RatingsConfig class, configure the ratings on a space to store the average of the ratings (without separate space ratings storage)
  • rate a page
  • login with another user
  • add another rating - the average rating is displayed on the screen
  • reload the page

Expected result:

• the average rating is still displayed properly

Actual result

• the average rating is not displayed properly anymore: only one vote is displayed, the first one
• if at this point the page objects are checked, the average rating object is not updated to reflect the new number of ratings and the average value

Important note: when used with the standard UI, the way this issue is perceived by the user is that their rating is not properly registered (upon page reload after adding the new vote, the displayed rating still displays only 1 vote and the old value).