I think there's a good argument that the intended interpretation should be the favored one. If he doesn't use the knowledge to always reveal a goat, why did they bother specifying that he has the knowledge?

But it still doesn't quite explicitly say that he's not picking randomly.

We only know that if the problem tells us. Sometimes it doesn't.

> There are no ambiguities in the Monty Hall problem

The problem has been written up thousands of times. I'm sure that some writeups are sufficiently unambiguous, but many are not. For example, consider the two "variants" described by this comment https://news.ycombinator.com/item?id=8664550

> The host selects one of the doors with a goat from the remaining two doors, and opens it.

> The host chooses one of the remaining two doors at random and opens it, showing a goat.

This commenter was trying hard for semantic precision, and yet, I think if you encountered the first variant in isolation it would be perfectly reasonable to interpret it as "The host [randomly] selects one of the doors with a goat [although he might have selected the prize]" even though this is clearly not what the commenter was attempting. If you disagree, that only proves my point: this problem is prone to silly and wasteful semantic debate, rather than the interesting probability result it should be focused on.

There's probably a name for that cognitive bias, but I don't know it.