Any accurate observations would depend on reading the entire will.
Generally, if the pre-deceased child has no children it will probably become a 3 way split.
If pre-deceased had children they should inherit on a per stirpes distribution basis.
Suppose deceased had 3 children. They will share deceased's share equally.
So, they share pre-deased's share (1/4) equally meaning that they get 1/4 x 1/3 = 1/12 of the estate each.
Some wills have a condition that survival is a condition precedent to the right to inherit.
If that applied here it would mean no inheritance to pre-deceased, their estate or issue [children].