I have a TSC3. Have been using it with no issues for a few years. in the last 2 projects, i've found that when i syn using office synchronizer, it manages to delete any measured control or base points i put in. When i measure them, they show up in the data collector and are usable. When i sync, they somehow manage to disappear. I didn't notice this last time i went out and had to re calibrate then entire site. Has anyone else had this issue?