There are many cache plugins site owners use for making their website fast and reducing resource usage and the common problem that comes is they do not know (cache plugins like W3 Total Cache and WP Super Cache) when a widget is updated and hence even after you make changes in your website widgets, they keep on showing that old content. In most WordPress cache plugins, caching system is no smarter when it comes to updating widgets.
This tutorial is on a simple WordPress plugin called Clear Cache For Widgets. It simply purges all cache on WPEngine, W3 Total Cache, WP Super Cache when updating a widget. Simply install and activate it and it will purge ALL your cache each time you save a widget.