We are having the same issue. We have 10 events that are scheduled to end on September 9th and instead are coming in with the following end dates:
October 10
October 13
October 16
October 21
November 8
November 16
November 25
December 11
December 19
December 25
We are running the latest version of Event Calendar and this is from an import this morning, but it’s been consistent for the past couple of months.