I am also building an AR app and getting "Failed to find reflection for buffer clusterIndexTable" in console. Did you ever figure out what the issue was?

This issue remains. The issue being that for some reason the house model is still not showing up in my scene after export. To illustrate this I'm attaching 2 photos. The first is showing my scene in reality composer with the house shrunk to 10% and just to the right of the stool. The second photo shows this scene as it appears on the iphone as a .reality file export. The house is not included for some reason. Still a mystery to me. Could it be a file size limit it is not telling me about?

Thank you so much. I will get him to do both. These guys have also created a backend for me and have hosted it on fast comet. I created an account and added them as users. Is that code something that should also be hosted in that (bitbucket) repository?