Rancher 2 Execute Shell Window Closed Unexpectedly

This video documents a behaviour on Rancher 2.2.8 (but also seen in previous 2.2.x versions) that the "Execute Shell" window closes unexpectedly. The close button was not clicked.
The issue is described on github.com/ran..., too.
Update: This happened on Kubernetes 1.13. Since the cluster was upgraded to Kubernetes 1.14, this issue seems solved.
Music credits: Martina and the air plan by Marco Castelli