The `main` target's depth buffer only contains the player's arm when fetched from post effects

I made a custom post effect with a resource pack, and attempted to fetch the depth buffer. However, only the player’s hand was visible.

I attached two screenshot, one with “use_depth_buffer“ true and one false.

I also attached my post_effect json file (test.json), the vertex and the fragment shader used.

The vertex shader is a rip-off core/screenquad.vsh with no effect.