Engineering design is being increasingly included in elementary education, typically to provide students with opportunities to apply science and mathematics concepts while developing their engineering practices. An important question is how to prepare teachers who can help students develop more informed engineering practices during classroom design tasks. In this multiple case study, we examine the engineering instruction of upper elementary (grades 3-5) teachers in the context of a professional development project. We analyze how those teachers provided scaffolding for a set of engineering design practices across 12 design lessons. We found that teachers provided substantial scaffolding for practices related to organizing the design process and attending to constraints when making design choices. However, with a couple notable exceptions, teachers provided minimal scaffolding for problem framing practices such as defining requirements and developing testing procedures. The professional development emphasized scaffolding strategies for problem framing practices, and so we explore reasons why they were so rarely implemented. We consider strengths and limitations of the pedagogical model that teachers employed, as well as a need to clarify practice-related outcomes for engineering instruction. We discuss implications and recommendations for elementary engineering instruction and teacher education.