diff --git a/versions/3.1.1.md b/versions/3.1.1.md
index 3737ffcf3c..69caeac281 100644
--- a/versions/3.1.1.md
+++ b/versions/3.1.1.md
@@ -2719,7 +2719,7 @@ Field Name | Type | Description
 
 This object MAY be extended with [Specification Extensions](#specificationExtensions).
 
-The discriminator object is legal only when using one of the composite keywords `oneOf`, `anyOf`, `allOf`.
+The discriminator object is legal only when using one of the composite keywords `oneOf`, `anyOf`, `allOf`.  Note that because the discriminating property's value is used as a component name and/or as the key in the `mapping` object, the behavior of any value that is not a string is undefined.
 
 In OAS 3.x, a response payload MAY be described to be exactly one of any number of types: