When Donald crosses before the bionic teens while introducing them to Tasha and Leo, Bree is suddenly missing from the line-up between Chase and Adam.
At the party after Leo's parents walk in, Chase is to Adam's right, but when Leo is driving the car, they have switched sides
When Bree hugs the lunch lady at school, Chase can be seen in the background waving at someone (possibly at Adam), but in the next shot he is completely turned around, picking the lock on a locker.