Hi Kellee, thanks for reaching out!
It sounds like your email client isn’t setting the reply-to correctly when replying. If you’re using a Gmail account that is the same as what you have in Admin > Settings > General > Admin Email, then it’s a known issue and you’ll have to either change the mailbox in the RBE connection or change the address in the Admin Email field. You should be using a dedicate mailbox for RBE anyway…
If that’s NOT the case, please check that the To field, when replying, looks something like this: [mailbox]+usc_[a bunch of characters]@[the mailbox domain].
Let me know what you find.