Hi MZ, back in the day, the laws of TT USED to call against these double hits, but more recent laws of TT state that now it must be an INTENTIONAL double strike.
How it is applied by umpires is that if there is a continuous swing and the ball his anywhere below the top of the wrist bone, the ball can strike say the side of finger and also then the racket. This would not be considered a double strike. Umpires look for the strike to be at wrist or below and a continuous swing.
I was about to point out the same thing, many don't believe me but I learned this at my FFTT umpire courses.