dfx generate bug

I tried the following:

1. include the ledger in a project with the following dfx.json

    "canisters": {
        "ledger": {
            "type": "custom",
            "wasm": "ledger.wasm",
            "candid": "ledger.private.did",
            "remote": {
                "candid": "ledger.public.did",
                "id": {
                    "ic": "ryjl3-tyaaa-aaaaa-aaaba-cai"
                }
            }
        },
        "trax_payments_backend": {
            "main": "src/trax_payments_backend/main.mo",
            "type": "motoko",
            "dependencies": ["ledger"]
        }
    },
    "defaults": {
        "build": {
            "args": "",
            "packtool": ""
        }
    },
    "version": 1
}

2. deploy the ledger, swap ledger.private.did to ledger.public.did in the dfx.json
3. include the ledger in another canister A using import Ledger "canister:ledger
4. deploy that canister A as well
5. run dfx generate A

I expected to see this happen: dfx generates the bindings for canister A

Instead, this happened:
dfx fails with the following output

❯ dfx generate trax_payments_backend
Building canisters before generate for Motoko
Error: Failed while trying to build all canisters.
Caused by: Failed while trying to build all canisters.
  The build step failed for canister 'r7inp-6aaaa-aaaaa-aaabq-cai' (trax_payments_backend) with an embedded error: Failed to build Motoko canister 'trax_payments_backend'.: Failed to compile Motoko.: Failed to run 'moc'.: The command '"/Users/moritz/.cache/dfinity/versions/0.12.1/moc" "/Users/moritz/projects/trax_payments/src/trax_payments_backend/main.mo" "-o" "/Users/moritz/projects/trax_payments/.dfx/local/canisters/trax_payments_backend/trax_payments_backend.wasm" "-c" "--debug" "--idl" "--stable-types" "--public-metadata" "candid:service" "--actor-idl" "/Users/moritz/projects/trax_payments/.dfx/local/canisters/idl/" "--actor-alias" "ledger" "rrkah-fqaaa-aaaaa-aaaaq-cai" "--actor-alias" "trax_payments_backend" "r7inp-6aaaa-aaaaa-aaabq-cai" "--package" "base" "/Users/moritz/.cache/dfinity/versions/0.12.1/base"' failed with exit status 'exit status: 1'.
Stdout:

Stderr:
/Users/moritz/projects/trax_payments/src/trax_payments_backend/main.mo:11.1-11.36: import error [M0009], file "/Users/moritz/projects/trax_payments/.dfx/local/canisters/idl/rrkah-fqaaa-aaaaa-aaaaq-cai.did" does not exist

This can be fixed by moving the ledgers did file to the path specified in the error message.

Meta

dfx --version:

12.0.1

<log output>

Start with the dfx generate command and the build step described in the report, using the supplied dfx.json and Motoko main.mo import as the reproduction. Check how the ledger.did file is placed under .dfx/local/canisters/idl; done means dfx generate A builds successfully and generates bindings without the missing-file error.