Sometimes I can get the page title and sometimes I can't

I am using the “JavaScript Tracking Client” API.
The page title is obtained from the response parameter “pageTitle”.
Even when tracking the same URL, “pageTitle” may or may not be included in the response parameter.

Question 1: What is the reason why the response parameter “pageTitle” cannot be obtained?
Question 2: If there are multiple causes, please let me know each one.
Question 3: Also, is it possible that the response parameter “pageTitle” cannot be obtained depending on the browser or communication environment of the person accessing the URL?
Question 4: What measures can be taken to ensure that the response parameter “pageTitle” can always be obtained?

Hi @hmk-fukushi-taiga

Can you exaclty describe the code you use to track the page title? (The Matomo API uses the page <title> to get the page title)

Are you also sure the page <title> is set before the track?