Details:
A pipeline that contains a docker in the highest scope level (in the declaration pipeline's code block {}) cannot change agents without the agent freezing and fails to run shell commands. This works however when the docker doesn't exist. This is easily reproducible and already contains a minimized jenkinsfile that confirms to fail and a minor change to the pipeline that shows that docker is the culprit.

Log output: None, the console output freezes.
After 5 minutes it states:
process apparently never started in /var/lib/jenkins/workspace/JOB@tmp/durable-63f1as1 (running Jenkins temporarily with -Dorg.jenkinsci.plugins.durabletask.BourneShellScript.LAUNCH_DIAGNOSTICS=true might make the problem clearer) and fails.

Step by step to reproduce the problem: 
A detailed description on how to easily reproduce the bug is in the stack overflow thread:
[https://stackoverflow.com/questions/61615429/jenkins-freezes-on-sh-commands-after-changing-agents
]

Circumstances: If the pipeline declaration block doesn't contain a docker block, this actually works. This is detailed in the stack overflow thread.

For more information go to the stack overflow thread.