With all the tests we’ve made on recent robots, I can almost guarantee you that the issue comes from cables, or more probably the connectors on motor boards.
Even if the robot is idle, a bad quality connector can mess up with communication. This is the case in some of the first robots we shipped. As for now, this problem doesn’t happen anymore (same software, same electronic boards, but improved connectors and cables).
Please contact our technical support and we’ll help you solve this! :)