Question: One of our staff members sent an announcement, and though it only shows in the portal once, the rest of us got the alert like five times? What's going on?
Answer: Sounds like your "sender" might have been just a little impatient, haha. We are aware of a bug that lets the sender click "OK" more than once, was fixed in our Portal Framework 7.4.1/Announcements 7.40 release that came out early Q2 2021.
Once you update, you'll be fine. In the meantime, remind staff to "only click once."