If all one knew about Fackrell's performance in the Bills game was 3 sacks in the box score, one might think he'd turned the corner after 2+ years of merely serviceable play. Let's break that Bills performance down a little bit:
On his first "sack", Fackrell was pancaked, laying on the ground, with his back to the QB. It looks like the refs blew that call with Allen tripping over the O-Lineman's foot wthout Fackrell touching him. If Fackrell had touched him, it would have been purely accidental. This sack is a garbage stat. Any credit for the Packer's good fortune on this play should go to Clark for beating his man and spinning Allen off his spot.
Then it was garbage time, under 2:00 minutes.
On Fackrell's second sack, he beat RT Jordon Mills off the edge. Mills went out with an injury on that play. While Facrell looked pretty good on the play, if we find out that Mills pulled a hammy on the play (I'm not finding a report on Mills at the moment) that might color the play a little differently. If it was the right ankle, then Fackrell did his damage before the injury.
The third sack was against the backup RT, Connor McDermott, a New England 6th. round pick in 2017 who was cut last year and then picked up by the Bills on waivers. Given the player and the garbage time situation, I'd call this a "preseason sack".
Fackrell had one other tackle, in the 3nd. quarter, stopping Allen for a 3 yard gain as he scrambled up the middle. That was a good looking adjustment to the play on second effort. But that second effort was only possible because Fackrell was pushed back two steps, disengaged into space by the LT on his pass rush.
This is not a 23 year old player reaching physical maturity. He'll be 27 in a couple of months.
We'll need to see more than this to begin thinking he might be more than a complementary player.