Trying to recall something strengthens the memory of it more than reading it again does. Re-reading notes feels productive because the material feels familiar, but familiarity is not the same as the ability to produce the answer under exam conditions. The feeling of fluency while reading is the trap.
Why it holds
Memory is strengthened by the effort of retrieval, not by exposure. Each time you pull a fact out of memory without looking, you make the next retrieval easier and more durable. Reading provides no such effort; it lets you recognise the material without ever producing it, and recognition is not what an exam tests. A past paper done under time is retrieval practice; re-reading the chapter is not.
Where it breaks
You cannot retrieve what you have never learned. The first pass through new material is necessarily reading. Retrieval practice is how you consolidate and keep what you have learned, not how you meet it for the first time.