I think this was the case because you have done a migration and something went wrong there.
Just to be sure check the other lang files if they are up to date to.
I don’t know any way to check if all files are on the last state sorry.
Edit: I think really something went wrong on your installation when migration and other files might be also not up to date, that’s because some webscripts don’t work as expected but I Dont know how to check if all is up to date 😬
Maybe someone of the Devs have a solution to start again, maybe the best solution is to make a new installation and then use the restore to have a clean installation again.