This is accurate and I had seen this with my GCMS notes as well. In my first set of notes my eligibility was recommended passed and "Assigned To" on the very first page had code of the Visa office (in my case code for Montreal VO). Visa office codes start with RC-XXXX. When it just shows the visa office code the application is in a general pool of applications. In second set of notes, received just after my PPR but generated two weeks before my PPR was triggered, the "Assigned To" on first page had a code of an agent. An agent had picked the case and assigned it to himself and the due date had changed to about a month from the date he assigned the case to himself. He did miss that date as well but by about 10 days. Looking at delays now I can't complain."what does your application is currently in queue for a review by an officer exactly mean?"
This is generally a final review queue. In my case, my eligibility is marked as 'Recommended Pass'. So the case analyst is satisfied with my application and has given his recommendation to the case officer. These cases are put in a queue along with other similar cases that are pending an officer's approval to proceed further. Unfortunately, once an application is in the final review queue there is no set date when the officer will review the file. Everything depends on the case officer's workload. Sometimes the review can happen in 2 days or 2 weeks or even 2 months but rest assured they will be reviewed. Once the officer completes his final review, the next step is usually passport request.
Here is a link to the post which shows difference in GCMS notes which I had written back then