I'm able to turn it off just fine. I'd normally suggest that there might be something wrong with user scripts / site scripts / gadgets because of T164116: Toolbar occasionally missing at no.wiki (due to some cookie issue?), but those aren't supposed to run on the preferences page.

I still can't turn this feature off in Firefox. Neither can I turn it off in Chromium. (Open source version of Google Chrome.)

Can it be … a Heisenbug?

You said on T164116 that clearing your cookies helped. Does it / did it help for this bug? Perhaps there is a broken user script / gadget on nowiki that significantly messes with your cookies to the point of breaking MediaWiki authentication?

@jeblad Are there any other reports of this not being able to be turned off, or is it just you? Are you able to change/enable/disable other preferences? If it bothers you I can always disable the preference for you on the server, but that's not a scalable solution of course ;)

I have deleted the cookies but it did not fix the problem. I'll check on another machine.

Same problem on Firefox on a Win10 laptop.

Very strange! I'll go in and manually turn it off for you. Can you then try turning it on again, to see 1) if that works and 2) if you're able to turn it off after that?

I just turned it off on the server side, can you try now?

Logged in with another account in a private Firefox window and it worked as expected. Logged in with my usual account in the same window and the bug was back.

It has been on for my account "jeblad" the whole time.

I'll wipe my commons.js, vector.js, and global.js, and see whjats happen.

Maybe you are running some JS code somewhere that turns it back on for you? I turned it off and saw that the rcenhancedfilters | 1 row had disappeared from the database, and now it has reappeared.

@jeblad Do you have "Automatically enable all new beta features" checked?

In T164118#3222629, @Mattflaschen-WMF wrote:

@jeblad Do you have "Automatically enable all new beta features" checked?

Yes he does: | 3482 | betafeatures-auto-enroll | 1 . You're right that that's probably the culprit. You'd think that that would let you opt out from a few individual beta features, but the "Automatically enable" preference is notorious for being broken in various ways.

Still stuck.

Bah! Turned off auto-enroll and now I can turn "New filters for edit review" off. I have turned "Hovercards" on and off several times to make sure nothing interfered, and that worked as a charm. :(

Okey, I have a 12kg frozen salmon, who do I spank?

But nice catch @Mattflaschen-WMF and @Catrope, then the culprit is sloppy code for Betafeatures! =)

I wouldn't say sloppy, but it's not implemented as you'd expect: T64815: BetaFeatures: "Automatically enable ..." should actually automatically enable, not require visiting Special:Preferences

In T164118#3222649, @jeblad wrote:

Okey, I have a 12kg frozen salmon, who do I spank?

Extension:BetaFeatures ;)

It looks like this bug is the flip side of T64815: BetaFeatures: "Automatically enable ..." should actually automatically enable, not require visiting Special:Preferences.

Then this would be a duplicate of T64815: BetaFeatures: "Automatically enable ..." should actually automatically enable, not require visiting Special:Preferences.