The authors of Book - Make it stick.. the science of successful learning highlight a common problem: Students tend to confuse familiarity with mastery of a topic.
This ''illusion of knowing" is one of the reasons that rereading is a popular strategy, even though Repeated exposure (like rereading) is an inefficient learning strategy. It is also closely related to the "Fluency illusion"
A lot of "blackouts" from students and "I got it in the lecture but the homework was impossible" are direct results of this very effect.
The illusion of knowing is also detrimental to choosing the right study technique, see The most effective learning strategies are not intuitive
General reference (according to the book):
Thomas Gilovich, How We Know What Isn’t So: The Fallibility of Human Reason in Everyday Life (New York: Free Press, 1991).