I just tried 4.17.2 and it didn’t solve the issue in standalone mode. Not only that, but the first time I updated the transform of an instanced static mesh, the editor froze for a good 10 minutes. I hope it’s not going to do that every first run… I didn’t try packaged.
edit: The freeze happens regularly, but I can’t figure out what sequence of events brings it. It’s always when I update the transform.