diff --git a/files/gitlab-config-template/gitlab.rb.template b/files/gitlab-config-template/gitlab.rb.template
index 498d8950297d22d1f9063d49db2d362a54c42cc5_ZmlsZXMvZ2l0bGFiLWNvbmZpZy10ZW1wbGF0ZS9naXRsYWIucmIudGVtcGxhdGU=..ce516a43b6673bcad6dc48743c38390f1e3f7f34_ZmlsZXMvZ2l0bGFiLWNvbmZpZy10ZW1wbGF0ZS9naXRsYWIucmIudGVtcGxhdGU= 100644
--- a/files/gitlab-config-template/gitlab.rb.template
+++ b/files/gitlab-config-template/gitlab.rb.template
@@ -1093,6 +1093,8 @@
 # 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`