Submodule checkout fails with Could not create directory '/.ssh' error if SSHCheckoutTrait is used

[Yanpas]

Jenkins and plugins versions report

Environment

TBD

What Operating System are you using (both controller, and any agents involved in the problem)?

RHEL 7

Reproduction steps

I have a multibranch pipeline with pipeline code stored in SCM.

The repo consist of projectA/repoA and one submodule projectB/repoB. Since these are different projects we can't use HTTP token and ssh is our only option. repoA gets checked-out fine, but when it comes to repoB I get this error.

Expected Results

submodules get checked out

Actual Results

Could not create directory '/.ssh' right when submodules gets checked out error.

Anything else?

I tried setting HOME=$WORKSPACE in job setting but no effect.

Are you interested in contributing a fix?

No response