Can't remove a language under "Reset or remove languages"

[Bellatrix86]

I accidentally clicked on a new language while changing my interface language through the settings. And now I can't remove it anymore.
The button that is usually red is now greyed out there.

Does it have to do with the fact that it is the only language in that interface? Because in the Interface language where I have two courses (from English) both buttons are clickable and in the other Interface where I have only one course (German) is is also greyed out. (I never noticed this before because I didn't need to.)
This new accidental course was in the French interface so it's the only one there too.

[Leila1126]

I have the same problem and it's kinda annoying to look at my profile with that course

[Usagiboy7]

Yes, I believe it is because that is the only language you've signed up for with that language interface.

[Mi335]

I have the same issue and I will still have 4 languages even I delete that unwanted language.
Is it because Dulingo use statistics to attract/sell their ads buyers so they don't want me to delete?.