Can you clarify what you mean by "got a link"? If you're using Send to Email, there shouldn't be any links involved. You just, well, send an email to the designated address with the ePub attached, and it shows up in your library shortly after.
FWIW I have been using that feature for well over a decade, with several hundred third party books in my Kindle library, and I haven't seen what you described once. Is the sender on the pre-approved list in Send to Email settings?
