Hi Stephanie,
Thank you for your post! This is something we are aware of and do have filed with our development team to resolve. Unfortunately on iOS, residual data can be maintained unless manually cleared (something we are working on currently). This doesn’t always occur with every import/layer, but can occur with some. If you haven’t already, please try turning the device on and off to try and clear some cached data. Unfortunately, the only other way to clear out this data is to uninstall and reinstall the app. Please keep in mind that doing this will cause a loss of maps/data that wasn’t previously saved or exported.
If you have any further questions about this process, please don’t hesitate to reach out to us via support.avenzamaps.com/hc
Kate
Avenza Support