If the time for an event on the mobile phone app calendar is not correct, check the timezone setting in the phone settings to make sure it is set to the correct time zone.
If you are not seeing calendar changes reflected on your mobile app calendar, then it is time to refresh the Mobile App. You can refresh from an android phone by: opening the app, go to settings, manage app, storage, then clear data & cache. For iphones: open the app, go to settings, click on reset app defaults.