Google sees the canonical page when checking, but not when indexing, what could be the problem?

Question

Search Engine Optimization

Hello, when checking on the site, it sees the canonical page, and when sent for indexing and further check from the index, it shows that there is no canonical page. (When it is not there at all, it writes "No) but now it is missing.
Please tell me what could be the problem? The page is completely unique, there is no more similar information on the site, with other links. The site is thematic. And the page that was created is 100% unique %.

Answer 1

The page is already in the index. What's wrong?