How to reduce PXI-6509 crosstalk?

I have a PXI-6509 board in a PXIe-1073 chassis, with an RG1005050 cable.  I'm using the DIO pins exclusively for digital output.  I'm controlling the 6509 using DAQmx and MS Visual C++.

When I set certain bits high, I'm getting "glitches" or crosstalk with amplitude of 3-4 Volts and duration of 20-50 nanoseconds.  The crosstalk is triggering my Device Under Test (DUT) and my measurement (oscilloscope) at undesired times.  I'm wondering if there's a DAQmx setting to slow down the rise and fall times on digital outputs, and thus reduce the crosstalk.

Thanks for any help or suggestions!