That is odd behavior and looks a lot like the following older bug that should already be fixed back in 2015, and should be working in current versions of the activity stream gadget, But to get a bit more context on your setup what version of Jira and the activity stream gadget are you currently running?
The Old Bug can be seen here:
Connect with like-minded Atlassian users at free events near you!Find an event
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no Community Events near you at the moment.Host an event
You're one step closer to meeting fellow Atlassian users at your local event. Learn more about Community Events