I have continuous crawl running on 2013 and everything I've read says that incremental crawl doesn't run if continuous crawl is selected but my crawl logs say different. Am I misunderstanding?
Answered my own question by reading this a little closer: A continuous crawl does not process or retry items that return errors more than three times. A "clean-up" incremental crawl automatically runs every four hours for content sources that have continuous crawl enabled to re-crawl any items that repeatedly return errors. This incremental crawl will try to crawl the item again and then will postpone retries if the error persists.