Party Pig Off-Flavors?

[igliashon]

Today I put my first batch of beer in a Party Pig for the first time. The instructions made it sound like the Pig itself should only be cleaned very gently (no hot water, no brushes, no caustics). So I gave it a long rinse in some warm water, sanitized it with Iodophor, and then filled it as per instructions. As I was filling it, I noticed a strong smell that I'd describe as "plasticky" or "medicinal". As anyone who's used one knows, at the end of the process you're supposed to blow off the gas until beer comes out, so I held up a bottle and caught some of the beer that came out. Well, the beer that came out tasted medicinal and very plasticky, just like the smell. It tasted totally normal before I put in secondary last week, and the carboy smelled normal as well. I don't *think* the beer got oxidized, though I suppose it's possible, as there was a good bit of excess head space in the secondary. What I want to know is, could there have been some kind of residue inside the Pig that my rinse and sanitize process didn't remove? Should I have soaked it in warm soapy water or something? Has anyone else experienced this kind of off flavor from a Pig?