Unable to credit uncredited actor

I wrote a contribution for Sonic Adventure to add Lani Minella as an uncredited voice in-game. She voices the Station Square Announcer in the English dub. The game is originally in Japanese and a section crediting English dub voice actors already exists in its credits.

However, when trying to add the credit I receive the following error:

The selected language matches the title's primary spoken language.Dubbing credits can only be added for languages that are not the title's primary language

This message is incorrect in this case. The primary spoken language of the game is Japanese, hence the existence of a section for English dub actors in the first place. Even when attempting to add the contribution, I see the Japanese name, Sonikku adobenchâ (1998) (VG).

Not only am I unable to make this submission, but the option to add the uncredited attribute is missing as well. Any help would be appreciated.