The first significant clue emerges about why Sitton was cut late:

“It was interesting. It was about a two-week long process, which was mind-boggling to me considering what I thought we had to get done,” Bakhtiari said in an interview on ESPN Wisconsin’s “Wilde & Tausch” that is set to air this morning. “But I’m very fortunate that the Packers were able to work with me (and we) were able to get it done and we were able to sign it the night before the game.”
He signed the deal Saturday the 10th. Two weeks before that is August 27th. That is one week before Sitton was cut and according to Bob McGinn, when the Packers realized they would need to do something.

https://t.co/am4iUCggzI