I have seen similar problem, if grid has allowaddnew=.t.
Chield column of the first record has shown wrong chield record
I set column with chieldren controlsource to unbound ( bound=.f.)
and in the got focus of the textbox in this
set value from chield table
gotfocus
this.value=chieldtable.filedname
Also I did seek of the parent key if parent key!=chieldkey
from parent into chiled table
Thats looks starnge, becase relation should care about it.
But all these tricks worked