It is a new world, thats been upgraded through the experiment snapshots, in singleplayer its just fine in realms it's broken.
I will be sending a visual demonstration in a bit here:
But Narnia, you can make a world in an older version with experiments enabled, and the issue occurs regardless. I've had that realm experiment world since the first snapshot and nothing is dropping, from chest nor blocks. It's really frustrating. I will happily dm with a staff member here on discord to resolve the issue if I must. That's how much I want this patched.
Here's the video https://www.youtube.com/watch?v=g-UryyhAL30
It's still broken and I am very irritated I don't know if it's just realms but that's what I've experienced it on, I am really irritated, 1.20.3 is almost here and it's so broken.
I can't get any new stuff with my friend, structures and mobs are fine, not loot items though. PLEASE fix this before 1.20.3 full release, I am willing to discord a dev to get it fixed, that's how desperate I am.