Either "Create polygon model" or "Create smoothed polygon model" options from datamanager manage to create the new node. However, once used, it no longer triggers the action again in a new call for any mask node.
I really tried but I was not able to reproduce this issue. For example, I created a segmentation and clicked multiple times on "Create smoothed polygon model" and "Create polygon model". Worked every time. I then created another segmentation in the same scene and did the same there with the same results.
Can you give us more hints on how to reproduce this issue?