This is due to a bug in the Color Correction Matrix core that if any one element is set as an integer, it automatically converts all of the elements to an integer.
The way to work around this is to make all of the elements either an integer or a decimal value.
i.e. 1 => 1.0
Please see (Xilinx Answer 32132) for a detailed list of LogiCORE Color Correction Matrix Release Notes and Known Issues.