@どんぐりキャノン ★
https://i.imgur.com/GVzvjei.png
Regarding this matter, redirecting read.cgi to itest is a bad idea.
You should use 「<link rel="canonical">」and「<link rel="alternate">」tag properly.

Currently, both the read.cgi and itest claim themselves as canonicalized URLs by the "canonical" tag.
As a result, Google recognizes the two types of pages as different pages.
https://i.imgur.com/NabIDK2.png
This will result in the ranking of two pages being split and penalized by Google.

Make read.cgi outputs「<link rel=”alternate">」tag that points to same page of itest.
And fix the "canonical" tag on the itest pages to point to the PC version of the page, not to itself.
Details:
https://www.google.com/search?q=link+rel+alternate

Please stop itest redirecting.