While Skip B’s protest is theoretically valid, the chances of the delivered bowl resting on the toucher are astronomical. Perhaps Lead A was showing off his ability to snatch a bowl out of mid air, perhaps he decided to catch it in order to prevent the displacement of the toucher at rest in the ditch. Perhaps he didn’t think about it at all; he just did it. You’d have to be the ultimate conspiracy theorist to think that a six-month novice was trying to prevent that bowl from landing on and sticking to the top of the toucher in the ditch. Tell Skip B his protest is NOT sustained. And, no, a bowl delivered by Skip A which results in a delay of Skip B’s protest would make no difference in this case.
As your current National-Umpire-in-Chief, I agree with the above answer, but only because the question states “at a daily draw game at their home club.” If I was officiating at an event where prize money is involved or medals are being awarded (think US Open, any Division Open, National Championships, and local tournaments), I would defer to Bowl and Jack Displacement, Law 37, to make a ruling, if asked to do so.