I tried this again, this time using something with a way less noise in it but I am not seeing the same level of artifacts that you are. Would you mind posting your Texture so I can play around with them? Testing with content that is similar to your gives me the following:
I do have a few artifacts in mine, which is to be expected, but the artifacts I see are not as pronounced as the ones you have which is quite puzzling. Granted it is only 9:30 in the morning so my not fully caffeinated brain might be missing something that is painfully ovbious. But in any case, if you post your testing Normal, I might be able to figure out what needs to be done to fix it.