Check the splices and redo them if necessary. Check the connector inside the RSS for corrosion.
I chased a similar problem to yours with a similar cable plant. Communication would be lost to the ISS, and it seemed like it was interference, sometimes from my laptop. I tried ferrite chokes and other mitigation techniques to no real avail.
Finally, I decided to troubleshoot the cable from end to end, thinking I perhaps had swapped a pair. As soon as I pulled the wall plate off by the console, the problem became evident. One of the data pair wires had broken off the keystone jack. It's a wonder that it worked at all...
Ever since I repunched that down, it's been flawless.
