I hope you found an answer to your question around, but in case you haven't, what you're seeing is a link redirect that Sendgrid uses. Sendgrid is our Jive Cloud mail partner, so this is expected. You'll most likely see this in email notifications coming from a Jive Cloud instance. And of course, the next question that frequently comes up on this topic is can this be changed? But unfortunately, the answer is no, not currently anyway.
Please feel free to file a case if you have any further questions on this.