error management during metadata build for edge case where the DF construction was "not expected".  Need to clean up logic so this isn't needed, j ust nice to have.

Signed-off-by: aj rossini <blindglobe@gmail.com>
access via xref to list of lists and df's based on list-of-lists.   Getting there!

Signed-off-by: aj rossini <blindglobe@gmail.com>