--- a/devtools/server/actors/object.js
+++ b/devtools/server/actors/object.js
@@ -788,17 +788,18 @@ const proto = {
     const retval = {
       configurable: desc.configurable,
       enumerable: desc.enumerable,
     };
 
     if ("value" in desc) {
       retval.writable = desc.writable;
       retval.value = this.hooks.createValueGrip(desc.value);
-    } else if (this._originalDescriptors.has(name)) {
+    } else if (this._originalDescriptors.has(name.toString())) {
+      name = name.toString();
       const watchpointType = this._originalDescriptors.get(name).watchpointType;
       desc = this._originalDescriptors.get(name).desc;
       retval.value = this.hooks.createValueGrip(
         this.obj.makeDebuggeeValue(desc.value)
       );
       retval.watchpoint = watchpointType;
     } else {
       if ("get" in desc) {