When I reported SPIGOT-7800, I noted it was very important that the player's loot table drops at their feet just like any other entity, and not at the position where their inventory drops (0.3 blocks below their eyes).

Despite this, the fix for SPIGOT-7800 moves the drops for both the player's inventory and their loot table to be 0.3 blocks below their eyes. Before the fix, the loot table did drop at the correct location, and only the player's inventory dropped at the wrong location.

You can test this using the same reproduction steps as SPIGOT-7800, but also install the minimal reproduction data pack attached to this issue. Following those steps with this data pack installed, a player head from the player's loot table should drop on the bottom layer of carpets, while any inventory items should drop on the top layer of carpets.

Currently, both the inventory and the player head drop on the top layer of carpets, preventing any data pack (such as the Vanilla Tweaks Graves data pack) from distinguishing between which items were from the player's inventory and which items were from the player's loot table. (It breaks more than that, but that's just one simple-to-explain example.)