I upgraded to Gigapixel 7 and I use it as a plug in. After the resizing and the file goes back to photoshop, the image size Width 1 inch, Height 1 inch, and the resolution is 1 pixel. I never had this problem with Gigapixel AI.
This is often reported when loading images into Photoshop after processing via Topaz applications. This might not necessary be Topaz’s fault. If the next application will not care about the metadata included it will look like that. At least the shown pixel size in width and height should aways be shown right because those are the only reliable data you get from an image.