Q: Inconsistent event syncing between iCal on MacBook

I'm on OS X 10.9.5 (Mavericks) on my MacBook Pro and iOS 8.3 on my iPhone 6. Some events sync, but others don't. Also, some events that sync are in a different calendar between iCal and iPhone calendar. All calendars are on and I've quite out of both programs. I've tried changing the calendar assignment, but it doesn't update. These are events that I created the day before and should certainly have synced by now. I did recently reloaded my OS running through the steps with an AppleCare representative (which managed to save my data). Any suggestions? Thanks.