Shallow submodules update not working?

Using git version 2.3.8 (Apple Git-58), when I try to clone a repository with submodules using option --depth 1, I get two different behaviors for two different commands:

# 1 - using git clone --recursive directly (OK) # repository last ref is cloned as well as its submodules $ git submodule clone git://repository --depth 1 --recursive

# 2 - using git clone then git submodule update (KO) # repository is cloned, then submodules are cloned too but an invalid reference is fetched leading to "fatal: reference is not a tree: <submodule ref>" $ git submodule clone git://repository --depth 1 $ cd repository $ git submodule update --init --recursive --depth 1 #error

I am wondering if the second scenario has the intended behavior, or if it should behave as the first solution. 

If this is the intented behavior, is it possible to retrieve a shallow version of submodules within an existing git repository, or the only solution is to clone the whole project with --depth 1 option?

Thanks,