Tommy is right, a little more info would help a great deal.
However, I'm guessing that if your filler is indeed 320LR, its probably a good wire. Could be wrong but I don't remember too many folks in the 320LR game putting out bad wire.
Also, I'm guessin its WM hot cracking, probably centerline, and 320 is really hot crack sensitive. Fully austenitic and Cb to boot.
this stuff needs to be run cool. Because even if you don't gt cracking you want to avoid the segregation of elements, as mucha s possible, since
Alloy 20/320 is generally used for severe corrosive services.