Reason of S Africa’s grounded jets not known

Bloomberg

Three airlines in South Africa took the unusual step of grounding some planes on October 22 after a regulator flagged compliance issues and ordered maintenance checks. Things got weirder when no one would publicly say exactly what needed checking.
The groundings by state-owned South African Airways and its Mango unit, plus Comair Ltd, which operates British Airways domestic flights and low-cost carrier Kulula, were big local news.
There were some delayed and rescheduled flights.
The disruptions followed Civil Aviation Authority inspections at South African Airways Technical, the maintenance provider for the airlines.
But what specific violations the inspectors found, and whether they compromised passenger safety, remain a mystery.
“The audit results revealed findings that put into question the airworthiness status of the said aircraft,” the transport ministry said in a statement, adding that compliance issues were identified without being more specific.