[DOCS] Add known issue to 8.14 release notes (elastic#189583)

docs/CHANGELOG.asciidoc

@@ -105,6 +105,8 @@ The 8.14.3 release includes the following bug fixes and known issues.
 
 include::CHANGELOG.asciidoc[tag=known-issue-186969]
 
+include::CHANGELOG.asciidoc[tag=known-issue-189394]
+
 [discrete]
 [[known-185691]]
 .When using the Observability AI Assistant with the OpenAI connector, function calling will result in an error
@@ -146,6 +148,8 @@ The 8.14.2 release includes the following bug fixes and known issues.
 
 include::CHANGELOG.asciidoc[tag=known-issue-186969]
 
+include::CHANGELOG.asciidoc[tag=known-issue-189394]
+
 [float]
 [[fixes-v8.14.2]]
 === Bug Fixes
@@ -170,6 +174,8 @@ The 8.14.1 release includes the following bug fixes and known issues.
 
 include::CHANGELOG.asciidoc[tag=known-issue-186969]
 
+include::CHANGELOG.asciidoc[tag=known-issue-189394]
+
 [float]
 [[fixes-v8.14.1]]
 === Bug Fixes
@@ -194,7 +200,6 @@ For information about the {kib} 8.14.0 release, review the following information
 === Known issues
 
 // tag::known-issue-186969[]
-[discrete]
 .Creating or editing APM, {observability} and {stack-monitor-app} rules fails
 [%collapsible]
 ====
@@ -208,9 +213,33 @@ This known issue impacts only {observability}, {stack-monitor-app}, and APM and
 *Workaround* +
 To work around this issue for {observability} and APM and {user-experience} rules, create them from the {observability} *Alerts* page.
 Refer to <<apm-alerts>> and {observability-guide}/create-alerts-rules.html[Create and manage {observability} rules].
+
+*Resolved* +
+This issue is resolved in 8.15.0.
 ====
 // end::known-issue-186969[]
 
+// tag::known-issue-189394[]
+.{webhook-cm} connector fails to send HTTP headers
+[%collapsible]
+====
+*Details* +
+If you configured the {webhook-cm} connector to send key-value pairs as headers, that information is not sent unles you have also enabled the basic authentication option for the connector.
+Refer to https://github.com/elastic/kibana/issues/189394[#189394].
+
+*Impact* +
+The impact of this issue will vary depending on the purpose of your headers.
+For example, if you added an `ApiKey` authorization header, you might receive a `401` authorization error since it's no longer sent by the connector.
+
+*Workaround* +
+To work around this issue, enable the *Require authentication for this webhook* option, which is the `hasAuth` property in the API.
+You must then provide a username and password for authentication.
+
+*Resolved* +
+This issue is resolved in 8.15.0.
+====
+// end::known-issue-189394[]
+
 [float]
 [[breaking-changes-8.14.0]]
 === Breaking changes