The Michigan COA interpreted In re Morris to require a conditional reversal when the parent asserted that his grandmothers were Native and:

It is unclear from the record exactly how or why the caseworker came to the conclusion, reflected in the case service plans, that the minor child is not an Indian child for purposes of 25 USC 1912(a); some elaboration would have been appropriate given the father’s assertion. There is no indication that an inquiry or investigation was made specifically with respect to the father’s claim made at the preliminary hearing, nor an explanation in regard to why the father’s claim was being discounted, assuming it was evaluated or pondered in the first place, such that the ICWA notice requirement was not triggered. Of special concern to us is that the initial case service plan, in its summarization of the trial court’s preliminary hearing order, made no mention of the court’s command that the caseworker “make necessary inquiry and/or notification as to possible Native American Indian heritage.” Furthermore, there is no clear confirmation by the court itself that its initial concerns of whether the child is an Indian child were alleviated. Moreover, the father’s assertion concerning the Native American heritage of the minor child’s paternal great-grandparents fits within the parameters of the examples given by the Morris Court, quoted above, that would trigger the need to serve notice. Morris, 491 Mich at 108 n 18. Finally, petitioner itself concedes that conditional reversal is necessary in order to determine whether the minor child is an Indian child under the law.

Opinion here.