Any edit to loot tables in behavior packs are being ignored by the game

I'm trying to make it so that Wither Skeletons drop Wither Bones instead of regular bones, but no matter what I do, the game just ignores my edited loot table file & uses the vanilla file instead.
I created the item for the custom Wither Bone, and didn't edit the location of the loot table. I even changed the min_engine_version in both my resource & behavior pack manifest to 1.20.0, and it doesn't fix the issue. This issue is effecting every loot table, not just the Wither Skeletons, and this applies to both vanilla & custom entities. Entirely custom loot tables don't work at all. This was not an issue before 1.20.0 released. 

I have attached both my resource & behavior pack down below.