Harry Potter and the Goblet of Fire - No Evening Moonrise Possible on 30 October 1994
It is established that HP part 4 must play between July 1994 and July 1995.
On October 30, 1994, when Beauxbatons and Durmstrangs arrive for the Triwizard Tournament, Ms Rowling writes that at around 6 PM, the moon had already risen over the Forbidden Forest.
This is not possible, as the moon on 30 October 1994 was only three days away from New Moon, and therefore on the wane. Waning moons cannot rise in the evening, not even in the "Magic World" :-)
To be more precise: Let's assume that Hogwarts is somewhere in Norther Britain. Moonrise time for Norther Britain for 30 October 1994 was 1:35 AM, i.e. totally incompatible with what Ms Rowling wrote.