Grounding the fleet is nothing unusual. During my 3 years on the flying frisbee the fleet was probably grounded at least half a dozen times (examples that spring to mind are 100% inspection and swap out of the CFM56s, cracks in flap/slat brackets, cracks in the frisbee 'clam shells', etc...). All perfectly normal as parts start to wear out for the first time.
I also remember the "amazing" Sentinel being grounded for a wiring snag with the radar and being so unexpected that they only had 2 sets of bolts for the radome - took weeks to resolve.
Probably nothing to see here and move on (as is usual in the press these days)
LJ