If a user has not reacted to any topic or message, then this page (/activity/reactions) gives an error

[Moin]

Reactions page glitches view when attempting to fetch more posts where no more posts exist

The access-denied issue appears to be a regression from a recent change, it should now be fixed with this commit: Logged in users should be able to see the reactions given by users from the Activity tab on the user profile again. The other issue of repeated requests and page jumpiness still needs further investigating.