Apparently GENEActiv stores "2010-09-16 09:10:00:000" as starttime in the file header when the battery is drained before the data is downloaded. The timestamp in the first page header is always expected to be correct and should be used instead.
See correspondence in google group: https://groups.google.com/g/RpackageGGIR/c/gltu_fATxfY/m/k7FMY7iDAAAJ
Apparently GENEActiv stores "2010-09-16 09:10:00:000" as starttime in the file header when the battery is drained before the data is downloaded. The timestamp in the first page header is always expected to be correct and should be used instead. See correspondence in google group: https://groups.google.com/g/RpackageGGIR/c/gltu_fATxfY/m/k7FMY7iDAAAJ