[docs] add not about 6.5 known issue

docs/CHANGELOG.asciidoc

@@ -91,6 +91,19 @@ See <<breaking-changes>>.
 [[known-issues-6.5.0]]
 === Known issues
 
+* {kib} gets stuck when upgrading from an older version
++
+After upgrading from an older version of {kib} while using {security}, if you get a permission error when you start {kib} for the first time, do the following steps to recover:
++
+1. Stop Kibana
+2. Delete the `.kibana_1` and `.kibana_2` indices that were created
+3. Create a new role in Elasticsearch that has the `all` permission for the `.tasks` index
+4. Create a new user in Elasticsearch that has the `kibana_system` role as well as the new role you just created
+5. Update `elasticsearch.username` and `elasticsearch.password` in kibana.yml with the details from that new user
+6. Start Kibana
++
+This will be fixed in a future bug fix release, at which time you can go back to using the built-in `kibana` user.
+
 * {kib} ignores the timezone setting `dateFormat:tz` {pull}25596[#25596]
 +
 If you use the default `browser` setting for `dateFormat:tz`,