Free shipping message showing old message no matter how many times I clear cache

I ran a sale and so put an extra message in the header banner with a discount code. That sale is now over and i would like to remove the coupon message. I have changed the message in the plugin settings but it still displays the old message in the banner header. I have cleared all my caches and even completely turned off the plugin altogether for a few days yet when I re-enable it, it still shows the out-of-date message.

Please let me know how to fix this issue. Also it flashes up the new message for a moment and then reverts to the out of date one.