Note that the visit of the F-35 RIAT had been officially canceled, as well as the first 2 days of Farnborough,
by the 12th of July, with the last 2 days being listed as "doubtful".
http://www.pprune.org/8560646-post4866.html
I suggest that the USMC had begun by that time to prepare their "return to Yuma" plan by that time, and when the rubbing problem and full-fleet inspection was announced on the 13th of July they dropped all Farnborough plans (as there was no possibility of completing the inspections in time to make it to even one day) and activated the preparations for "plan fly-home".
Remember that when the engine problem first was announced they said that the F-35Bs would have to depart 4 days before their initial appearance would be made.