diff --git a/docs/utils/debounce-event.md b/docs/utils/debounce-event.md
index bc61ed7..df9bc63 100644
--- a/docs/utils/debounce-event.md
+++ b/docs/utils/debounce-event.md
@@ -47,3 +47,9 @@ const eventsMap = {
 
 // provide the events map when creating your middleware or meta reducer...
 ```
+
+### Note
+
+The debounceEvent event does not currently support asynchronous events (see [comment](https://github.com/rangle/redux-beacon/issues/286#issuecomment-423023024)).
+
+This means that it is not possible to use `debounceEvent` with [`ensure`](./ensure.md) for the same [`EventDefinition`](../api/event-definition.md) (or the other way around).
diff --git a/docs/utils/ensure.md b/docs/utils/ensure.md
index a5db2d4..37b3726 100644
--- a/docs/utils/ensure.md
+++ b/docs/utils/ensure.md
@@ -57,3 +57,9 @@ const eventsMap = {
   LOCATION_CHANGE: ensure(isValidPageView, pageview)
 };
 ```
+
+### Note
+
+The ensure event does not currently support asynchronous events (see [comment](https://github.com/rangle/redux-beacon/issues/286#issuecomment-423023024)).
+
+This means that it is not possible to use `ensure` with [`debounceEvent`](./debounce-event.md) for the same [`EventDefinition`](../api/event-definition.md) (or the other way around).