Brindavan Express - ರೈಲು ಹೆಸರು ಬೃಂದಾವನ್ ,ಇದು ಯಾವಾಗಲೂ Number 1 - Vijay Baradwaj

You are pretty much correct Sir.The right terminology for this is #berthmultiplexing.
Kindly go to the availability page for VSKP-BZA/BZA-HYB/VSKP-HYB
Note the similarity. All of them are under a same quota with a slight difference in status here and there. Now that is due to #berthmultiplexing
For example, if I assume 100 berths allocated under General Quota, I would never know if...
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a booking has been made under VSKP-BZA leg or BZA-HYB leg or VSKP-HYB leg.
Assuming only 1 berth is left out, I would still have no clue where the previous 99 berths have gone. Now it may all happen that all of them have been booked from start-end, while all of them may also have been booked for VSKP-BZA Leg or somewhere enroute or it may also happen that it may have been booked for BZA-HYB leg or enroute.
In both the above cases (Apart from start-end), if the tickets are booked for VSKP-BZA leg or enroute, it shall clear the way for the subsequent passengers. Same is with BZA-HYB Leg. It shall clear way for passengers boarding and deboarding prior to BZA.
This train being mostly popular to passengers traveling to the intermediate station/s, confirmation chances are higher for the same. However, it is purely a risk game.
Kindly note, this has got nothing to do with #shortdistancereservation. It is simply how berth/s are manipulated and forwarded. A classic example of #berthmultiplexing