User ID "ID_004UKSJV" was created at month 12 of year 1. However, for this user I see an activity for month 1 of year 1 too. I'm guessing the datetime Year field of the user activity data is incorrect, and this year value should probably have been 2.
The order of month is 11, 12, 1, 2, 3, 4,
Okay?