Can a professor's assistant upload LOR?

[throwaway_backpack]

My professor is pretty busy this month with writing/sending a lot of letters for me and many others so they are having their assistant handle the uploading portion. So they want me to send the letter writer link to the assistant's email. Is this ok / normal to do? The letter will be written and signed by the professor but I guess I'm worried that if the email associated with the letter is obviously not the professor's then that might be inappropriate. Has anyone else had any experience with this? Thanks in advance!