Why does creating a mailbox create it in all namespaces?

When I create a mailbox using CREATE, it creates it in all namespaces? Is that supposed to happen? Look:

a namespace
* NAMESPACE (("" "/")("Other/" "/")) NIL NIL
a OK Namespace completed (0.001 + 0.000 secs).
a list "" *
* LIST (\HasNoChildren) "/" Other
* LIST (\HasNoChildren) "/" INBOX
a OK List completed (0.001 + 0.000 secs).
a create Other/Drafts
a OK Create completed (0.003 + 0.000 + 0.002 secs).
a list "" *
* LIST (\HasNoChildren) "/" Drafts
* LIST (\HasChildren) "/" Other
* LIST (\HasNoChildren) "/" Other/Drafts
* LIST (\HasNoChildren) "/" INBOX
a OK List completed (0.001 + 0.000 secs).

This is my namespace configuration

namespace {
  prefix =
  inbox = yes
  separator = /
}

namespace {
  prefix = Other/
  separator = /
}

And dovecot version is 2.3.7.2