FWIW, I just brewed a 1.047 English-style pale ale with S-04 and had a similar experience. It stopped burping and bubbling about 5 days ago, but I tasted it today & took gravity after 8 days in primary (I know, I know, I got antsy...) and it's still got a little way to go, but other than that it has fermented down to 1.010 fine. If the gravity doesn't change in the next few days I'll warm it up. Hope that helps!
PRIMARY: Simple Cascade APA
PLANNED: Black Nelson (BIPA)
BOTTLED: Saison, SNout Stout, Baltic Porter, Nelson/Maris Otter SMaSH, Centennial/Belgian Pils SMaSH