Hi there,
I'm opening this issue on behalf of the kubernetes-plugin users who are reporting those flaky/spurious issues in the fabric8 kubernetes-client repository.
Here you have a couple of links:

https://github.com/fabric8io/kubernetes-client/issues/5392
https://github.com/fabric8io/kubernetes-client/issues/5569

I have reviewed the code involved in the issue and I'm convinced that the execution of  this code:
https://github.com/jenkinsci/kubernetes-plugin/blob/7b3f77fb6f9b0018c82cbbdb2d5bee58defedf0f/src/main/java/org/csanchez/jenkins/plugins/kubernetes/pipeline/ContainerExecDecorator.java

can be improved to be more robust and handle the spurious failure that the users are experiencing.