terragrunt: Destination path already exists and is not an empty directory using --terragrunt-source-update

Hi everyone,

We have experienced the following error while trying to run terragrunt plan-all --terragrunt-source-update --terragrunt-non-interactive --terragrunt-include-external-dependencies

error downloading ‘ssh://git@github.com/project-terragrunt/secrets’: /usr/bin/git exited with 128: fatal: destination path ‘…project-terragrunt/secrets/.terragrunt-cache/M062klXZFj2B2dKtXGow5FueqdY/ZS8XBy97Un6SDm3LMf87-Dx8xEY’ already exists and is not an empty directory.

Our project has the following structure:

...
├── lambda
│   ├── LambdaA
│   │   └── terragrunt.hcl
│   ├── LambdaB
│       └── terragrunt.hcl
├── secrets
│   └── terragrunt.hcl
...

And we were trying to execute the command in the lambda folder.

LambdaA and LambdaB have:

terraform {
  source = "git::git@github.com:project-terraform//lambda/LambdaA?ref=branch"
}
dependency "secret" {
  config_path = "../../secrets"
}

We are currently avoiding this issue changing the reference to a certain commit and removing the flag --terragrunt-source-update, so we think the problem should be in the cache folder cleanup.