This ticket comes from the RFC mentioned in T184000

This is how I interpret the issue:

For users with very large watchlists, lag in changes being dispatched to clients can apparently cause 'new' changes for watched items to appear fairly far down the watchlist view.

For example:

• User is watching article A
• Item Q1 is edited on wikidata (linked to an article watched by the user on the wikipedia)
• 15 other articles are editing on the wikipedia the user uses and their changes appear in their watchlist
• Dispatching of the change finally occurs 5 minutes later
• The edit for Q1 / the linked page appears on line 16 in the watchlist? and can easily be missed?

This should probably be tested and confirmed.

A solution would be to order the entries in the watchlist by time added rather than time that the change actually occurred on wikidata.