I mean, he got up from under Ricky simon multiple times, got up from garbrandt and Aldo, too. It isn't like people haven't tried to keep him down in the past.
I think sandhagen just developed very good wrestling, especially while studying the dagestani style in prep for Umar, where as font was probay focusing on striking in prep for Song, thus his "triggers" or reactions for wrestling might have been a bit off for him where as cory's felt on.
Regardless, font came to the right conclusion in saying, "I need to train more wrestling".