I checked your save, and the gold from the Worldspell is counted.
The text next to your treasury total changes immediately to reflect your current treasury. For example, when your save is loaded it starts with 50 g (low). Casting your Worldspell increases your treasury to 125 g, and the (low) disappears.
The actual Vault in a city doesn't change until the next turn. For example, when your save is loaded your city starts with a Dwarven Vault (low). Casting your Worldspell causes no immediate change, but on the next turn the Vault is updated to a Dwarven Vault.
If your world spell is not cast, and your treasury is raised above 100 g by running cash then the same thing happens. The (low) disappears on the turn your treasury increases to 100 g or more, but only on the next turn does the Vault in the city update.
The Worldspell isn't bugged. The one turn delay on the Vaults may be a bug or just a technical limitation, I'm not sure which.