Modified event on map shown in wrong date

Hi,
maybe i’ve found an error on the behaviour of the map showing events.
I’ve created a map showing all the events of the day.
When an event previously created is modified changing its date, the event is shown on the map in the first date setted and not in the new date saved from the last modification.

Maybe it’s a known error, already corrected. I’m using the version 5.3.9, but i don’t want to update at the moment, because i made a lot of customizations on styles, also on the php code.
If it’s possible to solve the problem simply correcting some code (telling me what and where to correct), this will help me.

Thanks.

https://www.ads-software.com/extend/plugins/events-manager/