NTSB initial indications are that 2 1st stage fan blades separated. Very similar to the last event. The groundings could last a while. Lucky we have a bunch of C models just sitting around waiting to fly.
I don't know if they might be talking a 1 time inspection, then reduced intervals, or something more drastic like reduced time limited parts. More to come. Really too early to tell much.
I did fly an A model the next day before they were grounded.