CDN Cloudflare problems with search bots

My site uses Cloudflare CDN. I periodically receive notifications that the site’s robots.txt file has changed, although no changes have been made.

Periodically, in response to requests from search robots, the server returns documents with a ban, with the reason “Forbidden by the noindex element.”
The page was excluded from search due to a prohibition on indexing set using the robots meta tag with the value content=“noindex” or content=“none”. Although there are no prohibitions.

Search bots also see a page with the title “New title: One moment, please…” and the text “Please wait while your request is being verified” - this also points to Cloudflare.

How to fix this problem?