Content Translation shows a warning if the target title exists. It is also shown if the target title is a redirect, and this generally makes sense. Sometimes redirects in MediaWiki are done because this is an alternate spelling for the same subject name. However, it also often happens that the redirect actually has a slightly different meaning, and then the warning becomes confusing.
For example, in the Hebrew Wikipedia (at least today) there is the article "Municipality of Jerusalem" and there is also the page "Mayor of Jerusalem", which redirects to "Municipality of Jerusalem". In Russian, however, there is a separate page for "Mayor of Jerusalem". This article is shown as a translation suggestion from Russian to Hebrew, and when a user clicks it, then a warning is shown that a page with such a title already exists.
Though technically correct, this warning is confusing.
It would be better to show something like this: The article "Mayor of Jerusalem" exists in the target wiki and redirects to "Municipality of Jerusalem"