I've noticed a problem with the web API since the new website format went live. In the "issue" resource, the "publish_day", "publish_month" and "publish_year" values do not always match up with what I see on the website. There are two distinct examples (which may stop exhibiting the problem if someone ever changes the "In Store Date" or the "Cover Date" for either of them):
This comic contains no Cover Date, but it does have an In Store Date of March 23, 2013. However, when you access it with the web API, you get nothing for the published_day/month/year:
Other comics that do have a Cover Date seem to report the In Store Date in these fields as they should.
An even stranger example occurs with this comic, where we have a Cover Date of May 2013, and an In Store Date of March 27, 2013, yet the web API reports a mixture of the two dates!
On a related note, it would be really nice if the web API offered an addition "cover_year" and "cover_month" field so that API users could access both dates!