When Matt and Kay are in the cave, Matt trips over a rock as he is walking over to hang up Kay's bloomers to dry.
When Matt comes from fishing, he carries only one fish (left hand). Immediately after, he has two fishes.
After making it down the rapids, where previously we have seen Ms Monroe's clothes clinging soaking wet, the very first shot on still water she is all clean and dry and ironed. The same is true for Michum.
The chords Kay plays on the guitar do not match the chords necessary for that particular song.