What causes this at 19:00?

https://www.youtube.com/watch?v=1RlwZdc7pmg&index=3&list=PLk3T0fUh6FvQEMViTC4fGwVPAIsibCvbg

Copying and pasting from a youtube comment by MrWhitman

"This glitch seems to occur when there is supposed to be something that comes on screen but doesn't. Pretty much, the game goes into a loop trying to bring in the sprites (in this case the ghosts) but can't do so since the character was on screen when they should have come in but didn't. As for fixing it, there are always unforeseen consequences to changing the code so they probably just put in a message and left it due to deadlines."

(he recreates the glitch here: https://www.youtube.com/watch?v=2SoH-Kf_Gyk which is where I got the comment)

If I had to guess, it has something to do with the chief's throwing daggers in the thieves guild.

Worth noting that QFG2 has a reference to this bug - any time the fragmentation bug would occur, they actually fixed it, and have a cute little message about the hero squishing the bug underneath his foot. I remember that this actually came up at the end of a TAS after all the inputs - and the TASer couldn't add another input afterwards without desynching all the previous inputs.

I don't understand MrWhitman's explanation at all

I don't have a mind for programming, so I just take it that the ghost sprites didn't load correctly. Maybe it's just my faulty memory, but I could swear that I've randomly gotten that bug somewhere other than at the graveyard or the Thieves' Guild. Unfortunately, that was quite a few years ago.

Oh, I think I might understand. In the graveyard. MrWhitman entered it during the day, but then he rested there until night. At night, there are supposed to be ghosts there, but there weren't because he went there during the day and the screen doesn't change until you leave and come back. So that may have been the confusion there.

As for the Thieves' Guild, it was after midnight when he first went in there, so it could have been "Not Yet Dawn" when he left. I think you can't get into the bar if it's "Not Yet Dawn," thus you can't get into the thieves' guild.

So maybe this bug occurs if you enter a place at a certain time of day, and you stay there for a while, and the time of day changes, and things are supposed to be different if you're at that place at a different time of day. I guess the bug is that things are supposed to change as the time of day changes, but they don't change until you leave the screen so the game gets confused.