Yes it might, hopefully the ICC will clarify. To me it reads as 'wilful act of a fielder' so not relevant to anyone else in my interpretation. Some of us are wondering (in later posts) whether it is a clause to cover things like deflecting the ball or kicking the ball rather than something that comes specifically from a throw. So for instance a throw comes in, another fielder tries to deflect the ball onto the stumps with his/her foot and it then runs for four 'overthrows'. The 'timing' point will be the second person, not the first.
It seems clear cut to me. The clause differentiates between overthrows and wilful acts by the fielder. The "act" in the final sentence can only apply to "wilful acts by the fielder". Yesterday there clearly wasn't a "wiful act by the fielder" so only the reference to overthrows is relevant ie whether the batsmen had crossed when the ball was thrown.