Actually, the elimination feed is showing for test players in Debug mode for the published map mentioned above (for which I am facing an elimination feed issue for actual players), so I believe this issue is not caused by the custom UI.
I created a new map (published map), both without the custom UI (rank system) version and with the custom UI (rank system) version and test it with actual player, and I encountered no issues with the elimination feed in both cases.
This proves that the custom UI (rank system) is not the reason for this issue.
Videos:
Without custom UI(rank system)
With custom UI(rank system)
So, can you suggest any solutions for the issue?