Reported speech

[Rustamsher]

In one English Grammar Book, there is a type of exercises entitled "Correct the mistakes" and this 'incorrect' sentence is given:

Our teacher said to us that the test was quite easy.

In the key of the book as a correct version the following sentence is given:

Our teacher told us that the test was quite easy.

In the very same book the following rule is given:

We use the verb say both in direct and indirect speech with the preposition to when it is followed by the person being spoken to.

e.g. Jerry said to me, 'I need some money.'
Jerry said to me (that) he needed some money.

I wonder why is the sentence in bold above incorrect then?

Many thanks..

[Alan]

It is not incorrect, simply a little unnatural.