It isn't expected until one then learns enough comparative linguistics and etymology to discover that loanwords coming back has happened throughout history. And not just with European languages, although for obvious historical reasons the borrowings and weird routes that some words have travelled across multiple languages is far better documented for European languages.
It's a thing that happens with linguistic contact, and the deeper learning is that it's odd to expect it not to happen to the same word twice between languages with long-standing contact on occasion, given how often it happens and for how many millennia the process has been active.
It's a thing that happens with linguistic contact, and the deeper learning is that it's odd to expect it not to happen to the same word twice between languages with long-standing contact on occasion, given how often it happens and for how many millennia the process has been active.