Calendar Confusion Puzzle

The Puzzle:

If I said that in three days' time it would be a Thursday, I am sure that most of you would have no difficulty telling me that today was a Monday.

Try this one then. Yesterday was two days before Monday. What day is it today? Yes, you're right again. It's Sunday. Do you get the idea?

Now let's tackle a similar question from The National Mathematics Contest (1991) Paper:

Three days ago, yesterday was the day before Sunday. What day will it be tomorrow
?

Our Solution:

When I tested this, the order of popularity of answers handed in were: Sunday (9), Thursday (4), Monday (3), Friday (2), Wednesday (1), Saturday (1). THE RIGHT ANSWER WAS THURSDAY. Why?

Three days ago, yesterday was the day before Sunday, so three days ago was itself Sunday.
That means today is Wednesday, so tomorrow is Thursday