Duplicate callback outputs with identical inputs (and potentially different states) fail

Environment

dash                 2.9.2

Describe the bug

When 2 callbacks are created with a duplicate output (and allow_duplicate=True) and the same Inputs (States can be different), Dash gives a Duplicate callback outputs error.

from dash import Input, Output, Patch, State, callback

@callback(
    Output("deck", "data", allow_duplicate=True),
    Input("filter1", "value"),
    Input("filter2", "value"),
    State("state1", "value),
    prevent_initial_call=True,
)
def add_layer1(filter1, vilter2, state1):
    layer1 = load_layer1(filter1, vilter2, state1)
    update = Patch()
    update.layers[0] = layer1
    return update


@callback(
    Output("deck", "data", allow_duplicate=True),
    Input("filter1", "value"),
    Input("filter2", "value"),
    State("state2", "value),
    prevent_initial_call=True,
)
def add_layer2(filter1, vilter2, state2):
    layer2 = load_layer2(filter1, vilter2, state2)
    update = Patch()
    update.layers[1] = layer2
    return update 

Expected behavior

This should either:

• work, the use case is to load the data in several chunks / layers and return it with Patch so that things start displaying on the screen sooner
• or give a descriptive error message (something like "Several callbacks with duplicate Outputs have identical Inputs")

I assume that this is due to a hashing that is done based on the Inputs only, maybe it could include the decorated function name and the States in the hash as well?

Current workaround: Adding a dummy Input in the callback saves the day.

Screenshots