Hi Matt, yes, there may be more than one Render Subdiv Settings node, because I get the warning at the beginning of a render session. When I wanted to set the values inside like you recommended there was no Render Subdiv Settings node visible inside the renderer's internal network. So I copied one from another file like someone said in another post (as far as I remember). The file seems to accept the new settings, because all the shadow popping I had before I made these changes are gone.
So this seems to be the reason for the message in the animation check box. But why couldn't I find the original Render Subdiv Settings node? It seemed to be hidden somewhere...
I attached the file without objects and so on. You can see that there is Render subdiv settings 01_1, but the original one was and is not visible. It must be somewhere, because TG warns me before renderering that there can only be one of these nodes.