If you aren't seeing all your logged data in the reports (perhaps you are seeing all your sleep data but not any of your diaper logs), please check that you haven't toggled OFF any of the categories in the Filter settings of Reports.
You can check this by going to the Reports section, then tap on the filter icon in the upper right corner. From here you should see if Diaper for example is toggled on (it will be blue) vs. toggled off (it will be grey). Make sure to tap Apply to save changes.
Please see the screenshot below as a sample where you can find the filter icon on the app: