For now, the description is still vague and does not trace 1:1 back to a deliberate pilot (or someone else's) action.
The description suggests, it was a nose-down happening, so a pitch issue and no aileron input or engine failure or so.
The description doesn't say, whether this is a control column or trim happening.
A deliberate pilot action would not so much match with a control regain, halfway down and subsequently again a nose-down movement. Nor would a deliberate action match with the obvious attempt to "keep the airplane on course".
Strange thing is, we only do hear about the FDR results and not about the CVR, where the CVR might give the verbal pilot interaction, a more conclusive aspect around a deliberate action.
So, for now, the whole is far from conclusive (despite the world press jumping on the "deliberate" description).