I "patched" this error adding a for loop that removes multiple events with the same name inside last for of this method (in EventTimeline class):
public void apply (Skeleton skeleton, float lastTime, float time, Array<Event> firedEvents, float alpha) {
[...]
for (; frameIndex < frameCount && time >= frames[frameIndex]; frameIndex++){
/*
*HERE I CHECK IF AN EVENT WITH THE SAME NAME IS ADDED TO FIREDEVENTS
*/
firedEvents.add(events[frameIndex]);
}
}