We've heard that lots of our users also make use of the popular Series Engine plugin.
Unfortunately, this can occasionally conflict in various ways with The Events Calendar and Events Calendar PRO—it can cause events to be saved with the wrong date and time information, for example, or else to display that information incorrectly.
Thankfully, there is (in many cases) an easy fix: Simply look in your Series Engine settings for the Time.ly Plugin Compatibility mode and enable it. If you find that some events are still impacted after doing this, please try editing and re-saving the affected events, or even try recreating them completely.
Our thanks both to Andrew Wolfe for reporting this solution and also to Eric Murrell of the Series Engine team.