Our help department is backed up with articles to explain. I’ll try to dig up something I can share. @Theo, if you notice your model, it’s now marked as changed, and the template for your generate report is stored with your model. You should be prompted to save when closing, even if you didn’t otherwise modify the file.
@slbaumgartner, as @TheOnlyAaron mentioned, the new generate report is better because we keep it online, IMHO, and deliver updates, as we’ve already done once this week post 2016 launch. If you’re not online, you’ll revert to the old generate report, which had both an online and offline portion in earlier SketchUp versions.