The airline itself said it was due to technical issues, right after the plane landed.
Were there any cockpit warnings? Full loss of instruments? Conflicting information displayed? Stall warnings with overspeed warnings? Altitude holding problems on autopilot? Erratic system inputs? Before and/or after the mishap?
It will take quite an input to push passengers to the ceiling, an acceleration well beyond what the FBW system will allow.
This particular article addresses none of those points, only repeating what the airline said.
So until new information emerges, this mishap reads like a fairly classic inflight turbulence encounter. See, for instance, this event from December:
"this reads like a fairly classic inflight turbulence encounter"
Case-in-point being the Emirates flight from December, with similar ceiling damage, and similar passengers/crew injuries.