When Sadie is falls in the pool, she's shown to be barefoot. However, she is seen wearing her regular sandals right not 5 seconds before she fell, as well as after she gets out.
Right as Courtney and Harold are slap fighting each other, Izzy's umbilicus is missing.
In the flashback of Courtney and Duncan cuddling from [The Sucky Outdoors (2007)] Harold is nowhere to be seen.