I had this happen to me today. Reserved March 25th, Ordered December 15th. Dashboard said "Month of March" then "Month of April" then "Month of May", then "week of May 6th". Then I got a call from Nissan saying my car should leave the doc within the next week and arrive at my dealer toward the end of May. After that my "Week of May 6th" didn't change, until today.
Got an email from Nissan saying "your delivery date has changed". When I checked on it, my vin number had changed from 1840 to 2398.
I IM'ed with a CS rep at Nissan though the web site. They told me that my original 1840 vin Leaf had no release date from the dock now, and the new one, VIN 2398 had a release date and would arrive sooner.
I am with the previous thought that there might be something wrong with them that they are fixing on the dock. Something bad enough that they don't know how long it will take to fix them. I wonder if a large batch of the pre-EQ Leafs have some sort of systemic problem that maybe 1 in 5 of them or something is totally unfit to be shipped. They have been sitting there now for over 2 months now, this could be enough time for batteries to go flat and maybe not come back. (?)
I think the pollen excuse might be what the CS people were told to tell us and is really code for failed cells in the traction pack that need replaced or some other major component.