3 hour glucose test results

Got my results back . Failed . Nothing new I have a history of gestation diabetes. But I’m looking at my results and my #1 and #3 blood draws are elevated. How does that even make sense? So it went like this

Fasting-normal

Blood #1- elevated

Blood #2- normal

Blood #3- elevated.

Don’t your blood sugar go down every hour? So how was it normal for hour #2 but not 3!