In the VIP seats, Dr. Stella glances back and forth in Jacob's direction. She didn't expect to see him here. Although Jacob didn't disclose to her any personal information about him she did her research about him because she was obsessed with him.
From the information that she gathered about him, she knew that he is into a couple of martial arts like modified Judo, Muay Thai, and Krav Maga. And he also loves shooting. She didn't even find out when and where he met J. That's why she was surprised to find out that they were married. Among this information, being interested in car racing was not likely in his character.
Dr. Stella has been watching the race ever since her brother joined and she never missed a year. And during those years, she never saw Jacob. That's why she is wondering why he suddenly appeared this year.