When using 'p4.run("sync","//PATH/...") the Windows 10 slave drops the connection after 5 minutes every time. This was proven on a Webex using Wireshark.
If 'p4sync()' is used the command ran to completion (20 minutes). Potentially there is a problem with P4Groovy commands not displaying any output till the end of the command that is triggering this problem.
This ticket has been created to record the occurrence, allow me to try and reproduce the problem and to be a place holder where other reports of the same problem can be recorded.
Cloudbees support were unable to find a problem on their side.
Example jenkinsfile (in editor):