OPCUA server initialization

Hi All,
I'm using node-red-contrib-opcua nodes to create an opcua server on my application.
Sometime, during server initialization (when server struct is created) I have an error like "ns=1,s=FolderName already registered in namespace...".
It seems that the old opcua instance is still running after a project deployment.
I noticed that I have to create everytime the server struct at every project deployment,otherwise the struct is not created and the data not published ()ie server not working.
I cannot understand what the reason is.
Can anyone help me?
Thank you
Fabio

It depends what you deploy: Whole flow, modified flows or modified nodes.
Of course if server is not deployed it is running with the folders and variables that you have already added.