[RKBUmp]

Where is that statement from?

It is illegal to step onto the pitching plate with the hands already together. No rule set I am aware of has anything about allowing the pitcher to reset and correct the infraction. Once they have committed an illegal pitching act there is nothing they can do to correct it, it is an illegal pitch.

2017 USA Case Book
PLAY 6.1-3
May F1 take the pitching position with the hands already together?
RULING: No, this is illegal. F1’s hands must be apart when stepping onto the pitcher’s plate and while taking the signal. An illegal pitch should be called as soon as the violation occurs. (6-1A)

NFHS Case Book
Play 6.1.1 Situation A: May F1 take her pitching position with her hands already together? Ruling: No. F1's hands shall be apart when she steps onto the pitchers plate. Therefore, this is an illegal pitch.

2016 USSSA Case Book
SITUATION A: F1 takes her pitching position with her hands together.
RULING: Illegal, the umpire shall call an illegal pitch. (6-1-A)