If the .percolator mapping hasn't been created yet and two or more concurrent percolate index requests are processed, the first request would the .percolator type mapping, but the real time percolator listener wouldn't be active, this would result in that the subsequent concurrent requests wouldn't be parsed and kept in memory and would never be included in any percolate api result.

This issue only occurs when .percolator type is created on the fly and not when the mapping for .percolator has been defined before hand via put mapping or create index api.