#1 - Sept. 30, 2012, 12:49 a.m.
1. Authentication will randomly fail with 500 Invalid application signature errors, which never used to occur.
2. Random 500 series errors with both API and non-API responses.
3. Random 404 errors with both API and non-API responses.
4. The BattlePet Species API is returning duplicate "id" nodes for each item in the "abilities" array.
There may be others as well, but I think this is enough to say that something is definitely wrong.