QLineEdit input mask "A" accepts kana & kanji

QLineEdit input mask character "A" documented as "ASCII alphabetic character required. A-Z, a-z" at https://doc.qt.io/qt-5/qlineedit.html#inputMask-prop but it accepts kana and kanji. QLineEdit::hasAcceptable returns "true" when masked character is a kana / kanji character.

Steps to reproduce:

1. Run the attached project