README.md in opentelemetry-instrumentation-action_view-0.1.2 vs README.md in opentelemetry-instrumentation-action_view-0.1.3

@@ -34,9 +34,25 @@
 
 ## Examples
 
 Example usage can be seen in the `./example/trace_request_demonstration.ru` file [here](https://github.com/open-telemetry/opentelemetry-ruby/blob/main/instrumentation/action_view/example/trace_request_demonstration.ru)
 
+## Known issues
+
+ActionView instrumentation uses ActiveSupport notifications and in the case when a subscriber raises in start method an unclosed span would break successive spans ends. Example:
+
+```ruby
+class CrashingEndSubscriber
+  def start(name, id, payload)
+    raise 'boom'
+  end
+
+  def finish(name, id, payload) end
+end
+
+::ActiveSupport::Notifications.subscribe('render_template.action_view', CrashingStartSubscriber.new)
+```
+
 ## How can I get involved?
 
 The `opentelemetry-instrumentation-action_view` gem source is [on github][repo-github], along with related gems including `opentelemetry-api` and `opentelemetry-sdk`.
 
 The OpenTelemetry Ruby gems are maintained by the OpenTelemetry-Ruby special interest group (SIG). You can get involved by joining us in [GitHub Discussions][discussions-url] or attending our weekly meeting. See the [meeting calendar][community-meetings] for dates and times. For more information on this and other language SIGs, see the OpenTelemetry [community page][ruby-sig].