It can fail mid-way of course, but it really shouldn't corrupt in any other way. HTTPS is authenticated after all and malicious manipulation is harder to defend

It can fail mid-way of course, but it really shouldn't corrupt in any other way. HTTPS is authenticated after all and malicious manipulation is harder to defend against than accidental corruption. But this is reality and you can have bugs and errors outside the transport of course. Your file system could corrupt data, your drive could be bad etc. For security you want signatures with a known, trusted key.