So I tried the RT console on my laptop with the login that hasn't been playing alerts & I do get them on there. I also used a different Windows user acccount not the one I use on the machine that has the issue. I didn't want windows to sync anything in case that was the issue.
I have checked the account that I use on the machine that is not working on the laptop & I get alerts.
I've also uninstalled all audio drivers on the desktop not playing alerts & I still don't receive alerts after having the drivers reinstalled.
Could you try the IE browser TC with the original account that you experience the issue?
And a possible workaround. Could you ask your Rescue admin to delete and recreate your technician in the AdminCenter? I think it will work as a workaround.