I have a batch of, say, 25 items from my store. My app detects which ones aren't yet on Base, and adds them to an array ($to_add). Finally, there's a foreach loop that actually adds them to Base. One of the attributes added in the foreach loop is payment_accepted:

$newEntry->addGbaseAttribute("payment_accepted", "Google Checkout", "text");

I recently started getting "Expected response code 200, got 400". By commenting out selected parts of my code, I was finally able to narrow the problem down to this line -- if I comment it out, the error goes away. With further testing I figured out that of the 25 parts that get added, only one actually triggers the error. All of the rest go through fine. Comment out the payment_accepted attribute, and all go through.

How in the world can a static attribute be causing me so many headaches!? If all of the items go through fine without this attribute, then it can't be a problem with any of the other attributes... right?