I'm using ICSDroid to read in an Office365 ics calendar and sync with my Android calendar on a Samsung Galaxy S8 running Nougat. Although it syncs, I've found that the original events that have been cancelled or rescheduled are not removed, which means that they are still present in my calendar. If they have been rescheduled, I get duplicate events; one with the original times and one with the new ones.
I checked the ICS file to make sure that there wasn't an issue with it and it looks fine. I also read the same ics file with other desktop calendars and they are fine.
Let me know if you need more info. Any help would be much appreciated.