In reaction/reaction-received page on activity/notification, there exists a bug.
When user trying to scroll down and load the next page, there will be the same items added to the list, causing duplication.
The issue stems from a misalignment between the frontend and the backend. The id defined in the frontend is post_id while the backend requires reaction_id.
A draft PR is here, please review it when convenient.
Thanks for the draft PR, it does seem like pagination for reactions is inaccurate now and seems to repeat.
I am not sure if the correct fix is to set the post_id. It looks like pagination uses before_reaction_user_id (see here). Potentially even removing line 27 (the PR) would help since it’s likely set in the flattened reaction above.
To be clear I think the before_reaction_user_id should be the id from discourse_reactions_reaction_users - I think that variable name is somewhat confusing. Please feel free to clarify anything here or in chat.