blueberries are known to hermie.
When you purchased your BB beans, did you purchase older stock or newer 2014 stock? My seedbank (bonzaseeds) stocks the newest 2014 stock for auto BB (dutch passion) and i've grown it twice this year. One of the auto BBs has been through extreme stress (surprised it didn't drop dead!) and it still made it and gave me an oz!
Growing the auto BB again this year. have grown older stock of auto BB (older than the 2014 stock) and had a heap of issues.
Also buddy, you should snap off one of the seed-pod looking things and check inside if there's a seed; if there isn't a seed, it's just a swollen calyx full of T H & C!