I am spinning an ELK stack (6.6.1). Everything worked well, when suddenly all the "keyword" fields vanished from my items (new indexes, but also older ones that for sure did get those fields in the past). I have hard time trying to find documentation on how these fields are calculated. I've checked mappings which are good (it worked before btw, and there were no changes). I don't know where to search clues in logs or anywhere else.
Any help would be appreciated !