On mysql.test instance which has the latest 5.24 code, navigate to System Console and enable Group Mentions for any group and notice that the default group mention name is shown as some random alphanumeric characters
This issue was also seen on other test servers.
Please check this GIF to demonstrate this issue:
Note: I saw this issue on localhost during my testing, but when I ran `npm run dev` from mattermost-redux repo, the issue went away. Not sure if there is any dependency to be added while compiling the final mattermost exe which is deployed on these production test servers.