Thanks for reporting. I’ve added this to my todo list to handle this scenario.
This is quite rare condition where someone would every want to display an announcement empty.
Also in your case the message is coming out of a shortcode in random.
I’ll sure handle this in the next version.
For now if possible, you could do a simple code chagne like below.
This may or may not work as I’m yet to investigate the complete output on your side.
Please deactivate the plugin before making any code change.
In announcer/includes/display.php replace line 115