As previously announced , AdWords API v201309 and AdWords scripts will start enforcing a limit of 10,000 matching values as arguments for the IN and NOT_IN operators starting March 31, 2014 . This limit is currently enforced in AdWords API v201402.
You may be affected by this change if you construct large AWQL queries or selector predicates that have thousands of matching values using these operators in one of these use cases:
AdWords API
AdWords scripts
Retrieving items using the get method
Requesting reports using the report method
To make sure your applications and scripts work properly, check any code that constructs queries for reports or retrieve items using get or query methods and add necessary limit checks before March 31, 2014 .
If you have any questions about this change, you can post them on AdWords API or Scripts developer forums.
Anash P. Oommen, AdWords API Team