Unexpected conflict between two hashes of the same package

Entering the devshell defined in the flake [here](https://github.com/mlabs-haskell/spo-anywhere/blob/7f1ad4e0de0f960dd18c4020276908bbcb3e29a0/apps/keygen-commands.nix#L151) fails with: ``` error: collision between `/nix/store/3rm2zl7z4wb86yjix85icl828haylhqm-make-payment-keys/bin/make-payment-keys' and `/nix/store/p36kwgi2rxprjxam5znhh9yl4f1nkwk6-make-payment-keys/bin/make-payment-keys' ``` while the shell defines such a command just once. ### how to reproduce ```bash nix develop github:mlabs-haskell/spo-anywhere#spo-shell ```