Can anyone tell me why the text current effect is not being applied after placing the standard navar?

After placing the standard navar and setting up each page, the navar text will automatically become current when that page is displayed and the text color will change.
However, after creating several pages, I found that some pages do not change the text color.

The page has a child element, but the text display on the parent page is not changing. office is the parent page and the child element is a page named office_tokyo. I have not done anything special to the child elements. They are just named that way.

Does anyone know what is causing the text current effect not to be applied?
Is it still the name of the page or something else?
Or is it the navar link settings?

This post is using deepl, so it may be difficult to read.

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はじめまして Fedetaka,

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