GUI bug: Localized Audacity loses some access keys

I’m translating Audacity to Japanese.
This problem isn’t so usual nor fatal, but I’m glad if this minor inconvenience is fixed.

Though I don’t know how about other languages, at least in Japanese, access key is placed at the end of main string in upper case and enclosed in parentheses.

[EN]: Effe&ct
[JP]: エフェクト(&C)

The problem is that there are some cases where the access key with parentheses becomes invisible and only the main string is shown.

For example, when importing an audio file, three options (two radio buttons and one checkbox) appear in a warning dialog and each of them has its access key.
However, Audacity visually displays them as if they don’t have their access keys at the end.

[EN        ]: Make a &copy of the files before editing (safer)
[JP(ja.po) ]: 編集前にファイルのコピーを作成する (安全) (&C)
[JP(visual)]: 編集前にファイルのコピーを作成する (安全)

Red is the exemplified string and blues are the others with the same problem.
noAccessKeys_import.png
Another example can be seen on [Edit] > [Preferences] > [Recording] > [Name newly recorded tracks].
Four checkbox options lack their access keys visually.

[EN        ]: Custom Track &Name
[JP(ja.po) ]: カスタムトラック名(&N)
[JP(visual)]: カスタムトラック名

Red is the exemplified string and blues are the others with the same problem.
noAccessKeys_recPref.png
Note that the hidden access keys are just hidden and they do work.
In the second case above, pressing Alt+N toggles the custom track name successfully.

Thanks.

OS: Windows 7 64bit
my ja.po: https://github.com/Phroneris/audacity/blob/ad19061b11eef25e23e9201af12cb0f77bc2081f/locale/ja.po
Audacity version: 2.3.1-alpha-Nov 24 2018 (built by myself at commit 800ddae34b424a377ef4bbac16aac7638f93ad1b)

On Linux, these access keys only show when the Alt key is pressed.
This is what it looks like for me (English):

warning.png
Note that it is the character preceded by the “&” that is underscored.
How can that work if the localized text does not have the relevant character?

Then I tried three patterns.

no "&"  : 編集前にファイルのコピーを作成する (安全) (C)
no char : 元ファイルから直接読み込む (高速) (&)
no ")"  : 次回からは表示せず、いつも上記設定を使用する(&W

Result: all are visible.
noAccessKeys_import_test.png

I think you would do better asking about this on the translator’s mailing list, as that is where the translation experts hang out. (https://sourceforge.net/projects/audacity/lists/audacity-translation)

OK, thanks.