I don't have the plugins installed (Forest Pack, and some noise shader); I do get the same errors. They appear during the pre-processing phase before rendering begins. I had also turned off the NVIDIA denoising in IR and final, and was doing a final render. Also, in case it's relevant, when I hit cancel when it got to Rendering initial pass.... it didn't actually cancel, it's been showing the rendering dialog for an extra 2 minutes so far, not sure if it is ever going to actually stop :)