Same thing is happing in my site..
Sometimes I receive all the details correctly full but sometimes I receive the analytics section blank with strange dates: these dates are always the same when the parameters appear to be blank. While when I receive the analytics parameters correctly with all details, the dates are also correct.
Google Analytics information:
First visit: 01/01/1970 12:00:00 AM
Previous visit: 01/01/1970 12:00:00 AM
Current visit: 01/01/1970 12:00:00 AM
I have tried almost everything, including placing the analytics code in the footer section..
So if I understand correctly you are saying that the cause of this is that the users are blocking cookies in their browser, right?
Thank you in advance,