I confirm this bug with deja-dup-18.0. In my case LINGUAS is set to "es" but I had to compile deja-dup setting LINGUAS="" as stated in the previous comment.
I confirm this bug with deja-dup-18.0. In my case LINGUAS is set to "es" but I had to compile deja-dup setting LINGUAS="" as stated in the previous comment.