diff --git a/files/gitlab-config-template/gitlab.rb.template b/files/gitlab-config-template/gitlab.rb.template
index a468c5f9017033272d4437e81d6fca0fa5d35480_ZmlsZXMvZ2l0bGFiLWNvbmZpZy10ZW1wbGF0ZS9naXRsYWIucmIudGVtcGxhdGU=..f007f281cd43741b1e837f536e35ee062b32e040_ZmlsZXMvZ2l0bGFiLWNvbmZpZy10ZW1wbGF0ZS9naXRsYWIucmIudGVtcGxhdGU= 100644
--- a/files/gitlab-config-template/gitlab.rb.template
+++ b/files/gitlab-config-template/gitlab.rb.template
@@ -1095,6 +1095,8 @@
 # postgresql['log_truncate_on_rotation'] = nil
 # postgresql['log_rotation_age'] = nil
 # postgresql['log_rotation_size'] = nil
+##! 'username' affects the system and PostgreSQL user accounts created during installation and cannot be changed
+##! on an existing installation. See https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/3606 for more details.
 # postgresql['username'] = "gitlab-psql"
 # postgresql['group'] = "gitlab-psql"
 ##! `SQL_USER_PASSWORD_HASH` can be generated using the command `gitlab-ctl pg-password-md5 gitlab`