If you're seeing some questions again and again in the full-length tests, it's because you have exhausted those questions during normal practice.
Please note that even though we have 2000+ questions in the bank, each sub-topic (like triangles, age problems, etc.) has a limited number of questions, and there is a possibility of exhausting them if you take multiple quizzes on those topics.
This is why we advise you to keep at least 50% of the questions for the full-length tests so you can get fresh questions in every test.