Mail aliases plugin not honouring namespace?

I have

namespace { disabled = no hidden = no ignore_on_failure = no inbox = yes list = yes location = prefix = separator = / subscriptions = yes type = private } namespace Archive { disabled = no hidden = no ignore_on_failure = no inbox = no list = yes location = mbox:/home/mail-archive/%u/ prefix = Archive/ separator = / subscriptions = yes type = private }

Without aliases, folders are created at /home/mail-archive/%u/ which is expected

When I am adding these mailbox aliases

mailbox_alias_old = Archive mailbox_alias_new = Archives

These folders are created in the default namespace

.Archive .Archives.2018 .Archives

Is this as expected? I am at least not expecting it.