WSJ article for tomorrow's dated edition refers to an FAA AD issued in March 2019 in the wake of a similar occurrence (United 1175) in February 2018. Finally SLF/atty realized AD cite should be in NTSB report on that 2018 incident - report DaveReidUK had posted earlier.
So, link to AD 2019-03-01 pertaining to blade inspections and related:
2019-03-01.pdf (faa.gov)