If you read NSLocalizedString in the Custom keyboard, they won't read the .string file.

I have called NSLocalizedString in my custom keyboard code as follows, but they didn't read the appropriate Localized.string and I'm always having trouble with English.

data.append(NSLocalizedString("Notes", comment:"Event notes"))

It does not read the .string file in English, it simply appears to display the string of the NSLocalizedString argument ("Notes" as mentioned above).

We have added Base, English, and Japanese to Localized.string.

Localized.string Display

Project Configuration Screen

In addition, primaryLanguage in info.plist is set to mul, and the simulator and actual device languages are set to Japanese, and the region is set to Japanese.

Could you please advise me where I should check further?
Thank you for your cooperation.