[8.13](backport #4831) [8.18](backport) Manual backport missing from …

…previous PR (#4838)

* Backport 8.18 because missing (#4831)

(cherry picked from commit e2cf3fd)

# Conflicts:
#	docs/en/observability/apm/security/data-security/filtering.asciidoc

* Fix conflicts

---------

Co-authored-by: Eric <22215921+ericywl@users.noreply.github.com>
Co-authored-by: Eric Yap <eric.yap@elastic.co>

docs/en/observability/apm/apm-data-security.asciidoc

@@ -150,6 +150,10 @@ see <<apm-derive-client-ip>>.
 The capturing of this data can be turned off by setting
 **Capture personal data** to `false`.
 
+NOTE: This setting only prevents APM Server from capturing already ingested personal data.
+It does not prevent such data from appearing in ingestion logs where applicable.
+See <<apm-filters-in-agent,{apm-agent} filters>> for redacting data on ingestion.
+
 [discrete]
 [[apm-filters-real-user-data]]
 ==== Real user monitoring data