Ok, now I understand what you are saying. Whenever you use the word “schema” you are referring to the “example response” and that the example response shown in the documentation for both the v2 and v3 versions of those two endpoints doesn’t match the actual response you are getting from those endpoints.
In that case, yes, you have found a mistake in the example responses provided in the documentation for those endpoints, and the actual response you are getting is what you should ‘expect’ as being correct, in this case.
The problem probably originated back in August last year, when RFC-61 advised of the new Issue search endpoints and that a maximum of 20 Comments would be returned per Issue for those and other endpoints, and to get more Comments for any Issue, you’d need to use the new Get Comments endpoint per Issue. Looks like nobody ever updated the response examples in the documentation to match those changes.
Look through these Bugs in JAC for Jira Cloud that match ‘rest api comment’ and see if somebody else has logged that documentation Bug already. If not, you are welcome to log it yourself.