I never heard that before. I heard that the fact that they hold on to it means there is a high chance you’ll get it because if they want to deny you they would do so quickly. However, these are all assumptions. I heard they often call you in for an interview if they have doubts so Atleast that’s good, so they won’t just deny you without the interview once you pass the eligibility stage.
You should email the visa office though and see what they say. I did, but they didn’t give me much details they just said an officer is working on it and will tell me if they need anything or make a decision.