Third time’s the charm, as suggested by @Ladsgroup in T50047. I have since enabled enhanced RC because I value seeing Wikidata edits in my watchlist more, but the bug still exists in the same form in the setup I used before:

I don’t have an enabled setting for showing multiple edits from the same pages in my watchlist (‘Expand watchlist to show all settings, not just the most recent’), but Wikidata edits don’t acknowledge this and show each edit from Wikidata without checking for specific pages. I think that this behaviour should be fixed with showing me and others without enhanced RC only the latest edit.

This routinely brings my watchlist into disarray if one person on Wikidata edits an item too much:

Steps to reproduce:

1. Go to https://ru.wikipedia.org/wiki/Россия
2. Add it to your watchlist
3. Set up showing Wikidata edits in the watchlist if you don’t have it
4. Check the watchlist for 20+ edits in the same item Q159