Pigmen are spawned in the overworld and sent into a 2x2 killing chamber surrounded by 4 observer/piston pairs powered by redstone torches. Under one of the 2x2 blocks is a minecart, which is attached to a hopper, which is in turn attached to a sorter system.  The problem is that once a pigman is killed, his drops just float above the blocks instead of being absorbed into the minecart and hopper.  I also tried replacing the minecart with another hopper, and I tried replacing the block above the minecart or hopper with a slab.  Note that this design still works in the beta version in a world I had created in 1.18 with the same gold farm design.

See screenshot1 of minecart on rail with hopper underneath and screenshot2 with block replaced next to minecart.  See screenshot3 inside the kill chamber showing pistons and observers.  Screenshot 4 is the same view with the block covering the minecart removed. Screenshot 5 is a view of drops (golden swords visible) floating over the floor of the kill chamber.

Steps to reproduce:

1. Throw trident into one of the pistons of the killer.
2. Turn on killer pistons for a few seconds.
3. Turn off killer pistons.
4. Turn on sorter.
5. Turn on spawner. Pigmen are pushed into killing chamber via water.
6. Turn on killer pistons.
7. Note that pigmen are killed and experience orbs emitted.
8. Note that drops remain in the killing chamber instead of going into minecart or hopper.