Why does Yandex Webmaster write that canonical is affixed to all pages?

Question

HTTP headers

Hello, please help me to solve the problem. The webmaster received a message that the page code has changed and it responds with a 301 redirect, and so already 3 messages came from different pages,
the canonical tag also appeared on some pages, but the joke is that I didn’t put down redirects and there are no duplicate pages either, but such garbage happened only with those urls that are written like this /dostava That is, the transition through the internal links of the site, can this be the fault? That is, when following internal links, a redirect occurs from /dostava to https://misite/dostavka . I also thought that this could be due to subdomains, but Yandex says that these are not duplicates. Thanks in advance ))