Please reconfigure Field Maps to store data that is being collected directly to persistent (permanent) memory. When collecting long trail segments with high density collection (e.g. 1-2 ft / point), Field Maps starts to slow down appreciably and will crash and all the trail mapping is lost. Sometimes, Field Maps also crashes when battery saver is triggered or an application is changed (e.g. take a photo). Every time it crashes, the 1/4 mile to 1 mile trail segment is lost and has to be re-walked. I now collect very short sections and append them together, and carry a Garmin 66S to augment lost data segments. This does not make me happy as I am not leveraging my survey GNSS.
This behavior is seen in all my Android devices (Nokia 6.1, Samsung Tab 2, Samsung Tab 3, Samsung Active Tab2, and more) with various Field Map versions spanning the last two years or so.