At any time before an adjudication under this subtitle, a hearing on a preliminary motion on another issue, including an objection to the sufficiency of the petition, may be conducted without the child being present if the child’s testimony is not required. Except as provided in paragraph (2) of this subsection, any statement made by the child or information elicited during a competency hearing, in connection with the determination of competency, or while services are being provided under this subtitle, and any report prepared by a qualified expert, may not be admitted in evidence in any proceeding except a proceeding relating to the child’s competency to proceed. Paragraph (1) of this subsection does not apply if the counsel for the child introduces the report of the qualified expert, or any part of it, in any hearing other than a competency hearing.