Thanks for the quick response. I realize your original post, which a response to another question, was some time ago, and things may have changed. I just purchased Topaz and trying to integrate it into a workflow. In your original post you mentioned CS6, which caught my eye because it’s what I’m using (not planning to convert to CC). Please let me clarify:
Open NEF image in PS CS6, which brings the image into ACR. After making any changes in ACR, open in PS as a Smart Object. I assume this is what you were doing in your test. (Alternate: Open PS, file > open as Smart Object. Image opens in ACR, click Okay, and the image opens in PS as a Smart Object - same result).
Whether or not a duplicate smart layer is made makes no difference. I edit the smart object in filters > Topaz > DeNoise AI, then click Apply when finished. PS layer updates okay. When I re-invoke DeNoise AI from the layer, the initial adjustments are not saved. In your example they were saved. Just wondering what is different. Tried Adjust AI with same result.