Module with terrafile usage question

I have a private module injected with the terrafile

My terrafile

org ""
mod "abc", source: "", branch: "latest"

in app/stacks/foo/ I have

module "abc" {
  source = ""

  foo = ":BAR"

When I do terraspace bundle, I see my external module in `vendor/modules/abc`.
When I do terraspace build, I see my module in `.terraspace-cache/eu-west-2/dev/modules/abc`
When I do terraspace plan, I see my module in `.terraspace-cache/eu-west-2/dev/stacks/foo/.terraform/modules/abc`

When I have made a change in my external module, I did see the change everywhere except at the plan step that keep the previous version.

1. Is it the proper usage of module source (I start I was thinking it's "abc" as source instead of the source from terrafile) ?
2. If yes, perhaps adding an example in the documentation could be a plus.
3. What did I miss that make plan, not upgrading the external module?