After looking at the tape I can see where the issue is.
Sam Williams had 1 very legitimate pressure. He also had a late pressure (4+ seconds), but it was on the last play INT so I would probably give it to him. He also had three other "pressures" that are debatable...I don't feel like making a full video right now, but here are the screenshots of what I think are the debatable plays in question that NFL.com is likely saying are pressures.
Williams got depth and forced Russ to step up, but the Tackle just pushed him back out of the play.....I wouldn't say this is a true pressure, but it depends on how you want to grade I guess. If the DTs get any sort of push up the middle restricting the QB from stepping up it could be a bigger play, but the RT forced Williams to go around Russ. You'd like to see Sam Williams actually get around the outside should of his man and turn the corner to consider this a true pressure IMO.
Again he gets push....but I wouldnt say this is pressure. Gotta beat your man and not just get depth.
This is the INT in OT....The pressure came a little late, but I think you have to give this one to him. In the face of the QB as he throws, I'll take that every time.
This is the Kenny Clark sack.....Williams got an initial push but never really defeated his man. I wouldn't count this as a bad rep, but I can't give him credit for a pressure either.
Overall not very impressed with Sam Williams in this game at all. I could be missing one as I went through the game tape pretty quick, but I only counted 1 legitimate undeniable pressure from Williams in 30 pass rush attempts. I'd also give him credit for a 2nd on the INT if I'm doing the grading.