Event Editable: When edit a specific event, other events on the same group unexpectedly edited same as that specific event - fullcalendar

Question

I am trying the editable, drag and expand event on my FullCalendar.
First of all, I am using React.
To describe the problem:
If I have this 2 events on my calendar with same group:
before drag and drop
Event1 is Workshop#1pm, Event 2 is Date#5pm
When I drag and drop Workshop to 12 pm, the same will goes to Date and it will located at 4pm, at the same time.
after drag and drop
Same thing happen with changing duration.
I only want single event to be affected with the gesture, not all event on its group.
So far, I tried to read the documentation thoroughly but I could not find any settings related to it. I also tried to search forums but I never found similar problem.
I am suspecting it has something to do with my complex style of populating calendar with event.
constructor(props) {
super(props);
this.state = {
myEventSource: [],
}
// function the fetch event from google API
loadEvents = async () => {
await fetch(fetchCommand)
.then(res => res.json())
.then((res) => {
// making the loop
res.result.forEach(result => {
// when get result, it will compose the events object to be
// stored in this.state.myEventSource
var tempEvent = [];
result[0].eventsInfo.forEach(event => {
var evt = {
id: event.id,
groupId: result[0].userName,
title: event.summary,
allDay: event.start.date!=null?true:false,
start: event.start.dateTime!=null?event.start.dateTime?.toString():event.start.date?.toString(),
end: event.end.dateTime!=null?event.end.dateTime?.toString():event.end.date?.toString(),
}
tempEvent.push(evt);
});
this.TempEventSource[result[0].userName] = tempEvent;
});
});
...
this.setState({ myEventSource: this.updateCalendarOnTabChange(this.state.tabIndex), firstLoad: true });
}
render() {
return(
<FullCalendar
plugins={[ timeGridPlugin, dayGridPlugin, interactionPlugin]} //
editable={true}
...
eventSources={this.state.myEventSource}
/>
)
}