It sounds like you didn't SAVE it. Let's try the same process again. Open the desired LEG to edit and then tap SAVE on the top right, close APDL, turn your phone off. Whether your phone is offline or not makes no difference, the sync system will detect that and not try to sync it. Now turn on the phone, open APDL and view the Leg. Are your changes persisted?
Please go to the Communication area of the app and submit a problem report if you require further assistance and we'll review your log files.