My experience with the Nik Collection team is the same. Since DxO won’t update you on their progress and plans, it seems necessary to break the workflow up into steps to see where the problem is occurring. Is it possible for you to isolate Nik and the Adobe software? For example, if you’re sending an image to Color Efex Pro, try exporting to a TIFF file instead and then bring up the TIFF file in Color Efex Pro. Then in Color Efex Pro save the work to the same TIFF or to a new TIFF and examine that file to see if it’s corrupted. Bring the saved image back up in Adobe: is it displaying correctly? Does exporting to different image formats and file formats (TIFF with compression, TIFF without compression, 16-bit, 8-bit, etc.) make a difference?
I expect that both DxO and Adobe software will work with 16-bit TIFFs, with or without LZW compression and any other options you might want to choose. If there’s something incompatible with the way the two handle compression or the TIFF container itself, I hope it will show up in these tests. If the problem is more internal to how the two software packages communicate with each other, or with memory or cache or some such component of the system, it probably won’t show up in these tests. (I can only offer theories because I don’t know how all the components of the system interact.)