Multi percolate order

I am developing a software with elasticsearc and i try to use the multipercolate from ES1.5
In the API documentation about the response of the multi percolate it says :

Each item represents a percolate response, the order of the items maps to the order in which the percolate requests were specified. In case a percolate request failed, the item response is substituted with an error message.

I am masking the response of multi percolate, with the data that i insert in the mpercolate bulk insert, evan if the response size and the size of the std::vector in which i temporary store the documents, are same , the data which response to percolate is not the correct one, that i think the order of the multi percolate response is not correct. This usually happens when the size of the bulk insert is over 2000, is there a limit?

Best regards
Adrian Sandu