I haven't had that particular beer, but I'd say you probably got a bad six pack. I've never tasted anything plastic-like in any of the ESBs I've tried.
Up Next: Saison, Tripel
Primary: Accidental Lambic
Secondary: Chili Pepper Smoked Porter(s)
Bottled: Brett B. Tripel, Dubbel, Robust Porter, Black IPA, Cal Common, Chinook/Vienna SMaSH, Kolsch, APA, ESB, Oatmeal Stout, Tafelbier