I think in the Eagles game that Williams was called down by contact rather than forward progress stopped.
This from AI in response to "can down by contact be challenged nfl if there is a fumble": Yes, a play involving a runner ruled "down by contact" can be challenged in the NFL if a fumble occurs immediately after the call and is recovered by a teammate or opponent, allowing for a review of whether the ball was actually fumbled before the runner was ruled down.
And in response to "can forward progress be challenged nfl if there is a fumble": No, the judgment of forward progress itself cannot be challenged in the NFL. However, if a forward progress call is made but the play involves a fumble, the play can be reviewed to determine if the fumble occurred before or simultaneously with the forward progress being stopped, which can change the outcome of the play. <My take: the refs blew the whistle when they determined that forward progress was stopped and the fumble came after the whistle.>
AlbaNY_Ram
