When it happened to me recently it was a local community college, definitely not just scraping data. It makes it that much more frustrating too because I thought the interview went well and I will never know what they were looking for that I didn’t have.

Not necessarily.

While it’s true that the job listing was probably fake, the reason for listing it is often to collect data on the current hiring pool, including how much response can be expected when listing a role with varying salaries. HR departments take this insight back to their current employees and use it to decide who to give raises to and who can be replaced by someone new who will work for less.

That or its a scam to get temporary foreign workers

There is a lot of that. But there is also a lot going on behind the scenes that can cause a posting to be pulled. Particularly as spicy (shitty) as the economy is these days.