Re-examine connection between connectors' shield and GND
either R = 1MΩ and C = 4.7nF (1) or ferrite bead (2,3)
(1): http://ww1.microchip.com/downloads/en/Appnotes/doc8388.pdf
(2): https://www.picmg.org/wp-content/uploads/PICMG_COMDG_2.0-RELEASED-2013-12-06.pdf