Filters are available by default on Watchlist. Whether you have the filters on Watchlist is supposed to be controlled by the Beta preferences. I've tried to change my preferences using my WMF account and my volunteer account on Wikidata with no change, apparently. @Lea_Lacroix_WMDE tried it as well with no success.
I have that issue on deployment train phase 0 and phase 1 wikis (mediawiki.org, all non Wikipedias, Wikidata, Catalan Wikipedia)
On phase 2 wikis (fr.wp, es.wp), I've been able to enable and disable the Betafeature.
Opt-out the Recent Changes improvements in preferences turns the Watchlist to the default state (no filters).