The bottle of PhotoFlo that I've been using for years finally ran dry, so I pulled a bottle of the Freestyle equivalent off the shelf. At about the same time, I started seeing spots on my negs. I suspect those spots are left over surfactant residue. I've actually had this in the past with PhotoFlo as well; I don't think there is anything generically wrong with the Freestyle stuff. More like I got a bad bottle. It also may have been fine when I got it and since gone bad. The Freestyle bottle had been sitting around for at least a year but probably much longer.
The residue seems to wash off, although rewashing cut negs is a pain in the ass, so I may skip it for all but a few negs. When I went looking for a new bottle of PhotoFlo, I discovered that B&H no longer ships it, but they do ship Edwal LFN. LFN comes in a dropper bottle, which would let me skip the process of measuring out surfactant in a baby medicine syringe. It seemed to work fine on the rewashed negs, but only a larger test will tell.