Continuity mistake: When Red Buckley is about to enter Emil Duval's house at night before discovering the black pearl, the lights inside the house are on, but when he finally enters the house they are off. Later when he goes out, they are on again.
Creep Course - S5-E9
Continuity mistake: Professor Finley left behind the tool for removing the brain in his study. Stella somehow has it later in the mummy's tomb.