With EntityCulling 1.6.2 on 1.20.1 Paper server, I dropped some items around me, those in front of me flashed before disappearing, but I turned back finding those behind me didn't flash and disappeared suddenly. Works normally without EntityCulling or adding minecraft:item to EntityCulling entityWhitelist.
With Carpet 1.4.112 on local game, I accelerated the game with respectively tick warp and tick rate, and items disappeared without flashing.
Minecraft 1.20, Fabric Loader 0.14.21, Fabric Api 0.83.0, ClearDespawn 1.1.11, Autofish 0.9.10 (testing with other mods) or Cloth Config 11.0.99 (without other mods), tested with and without other mods and had the same results.