Well, technically that would be the case, but it isn't that easy.
Here, if you say, the children of the 'original convert' keep changing their religion back and forth, yet end up as Hindus during the time of when the partition takes place, (and thus become entitled to inherit,) the other party who's also entitled to the share during the time of such partition (say, someone from the relative's side) may use the claim of such tendency of children (of changing religion) to object to the share of the children in question, and they may have a valid point, for the court may deem that the children are taking advantage of their own wrong, and also undermining the sanctity of religion if they do that. (i.e. changing religion to inherit property; so as to derive personal benifit, and then conveniently changing it back.)
This would undermine the credibility of the children. The court may thus disqualify on such grounds if the other claimant party (Hindu) 1)objects and 2) is successfully able to make this case.