I had a bad pack of Wyeast 1335 last month, but I thought it was my fault. I ordered it online even though I don't usually do that, but it pushed my order over the threshold for free shipping. I am close to the MoreBeer warehouse, so I usually get orders in 1 day, or 2 at most. I ordered an ice pack, anyway. It turns out that they shipped from PA instead of CA, and it took 6 days to get here. The yeast and ice pack were warm. I tried to make a starter, but it didn't grow. I went into the local MoreBeer store to get a replacement from their fridge. When I told the store manager my story he gave me the replacement for free, and I assured him that I had learned my lesson about buying yeast online. The next starter worked fine, and the beer turned out great.
Another lesson I learned is that making a starter well ahead of time is a good idea. That way you can be sure you have good yeast, and it gives you a chance to get a replacement if not.
I assumed that I had screwed up and that the yeast had gotten overheated in shipping. Maybe not...
--GF