Graham can talk to Prince Herbert after talking to his fiancée, Alicia (the princess who was turned into a weeping willow). But Graham will still tell Herbert, regardless of having encountered Alicia and learning of her predicament, that he hasn't seen or heard of anyone like her.
If the player forgets to use the beeswax to patch the hole in the boat, which Graham uses to find Mordack's island, the boat will sink. As it sinks, Graham starts calling for help and he still does it as soon as he's underwater.
Immediately after Graham restores Alicia to human by retrieving her stolen heart, Prince Herbert suddenly appears from nowhere to reunite with her.
When Graham is locked in the cellar at the inn, it's specified there's a padlock on the door, which is on the inside of the cellar. How could the innkeeper lock the door with the padlock on the inside of the cellar without locking himself in?
Upon encountering the rattlesnake in the Serenia woods, Cedric warns Graham that it's "a poisonous snake." However, he is grammatically incorrect, because rattlesnakes are venomous (they inject toxin), not poisonous (toxin is absorbed, consumed, or inhaled). The narrator, however, correctly acknowledges this distinction if the player "looks" at the rattlesnake ("A large, venomous snake eyes Graham's passage to the east.")