I say inconsistent because an identical query will sometimes work, and other times I get an 'unable to complete operation' error. The queries are extremely simple, for example the where clause is "COUNTRY_ID = 2", and I am positive its not the where clause because it always worked coming from ArcGIS Server 10.0.
Testing the query in the REST page directly from the services directory yields the same result. My result alternates between success and error - query 1: success, query 2: error, query 3: success, query 4: error.
Has anyone experienced something similar?
UPDATE: From info I found in this post, I found that making POST requests resolves my issues.