Cross reality laboratories are widely used in education, yet research on the usability/user experience (UX) of these laboratories is still lacking. This study wants to start the discussion about challenges for usability/UX by interviewing practitioners from a large project for cross reality laboratories spanning multiple institutes in Germany. A total of 18 challenges were discovered, together with three target groups, namely, developers, maintainers, and learners. In addition, the tension between developers and usability is discussed. Open questions include the need to conduct further research with different target groups and how to increase usability for laboratory developers.