Thank you for your post. While we generally recommend Helium as a backup method for Android devices, we cannot guarantee it’s full functionality and that it will work in all cases. We do not test with Helium on a regular basis, and as it is a 3rd party app, there can be a lot of variation not only in its own functionality but with your device, the files you have, etc.
In regards to the memory issues, this is often related more-so to the device and the number of maps that you are trying to maintain both on your device, and within Avenza Maps. For example, if you are keeping a constant 150 maps loaded in Avenza Maps, the app is keeping these maps processed and accessible at a moment’s notice so the memory usage will be higher. We recommend users try to keep only what they need in the app in order to prevent the device itself (not the app) from maxing out memory, etc. which could result in a loss of data.
Please don’t hesitate to contact our Support team directly (help.avenzamaps.com) if you have any further questions regarding this.