a first try

packages/babel-polyfill-provider-corejs3/src/index.js

@@ -124,6 +124,15 @@ export default ((
     },
 
     usagePure(meta, utils, path) {
+      const isNamespaced = path => {
+        if (!path.node) return false;
+        const binding = path.scope.getBinding(path.node.name);
+        if (!binding) return false;
+        return binding.path.isImportNamespaceSpecifier();
+      };
+
+      if (isNamespaced(path.get("object"))) return false;
+
       if (meta.kind === "in") {
         if (meta.key === "Symbol.iterator") {
           path.replaceWith(

packages/babel-polyfill-provider-corejs3/test/fixtures/usage-pure/modules-namespaced/input.mjs

@@ -0,0 +1,2 @@
+import * as bar from "bar";
+bar.map();

packages/babel-polyfill-provider-corejs3/test/fixtures/usage-pure/modules-namespaced/options.json

@@ -0,0 +1,11 @@
+{
+  "plugins": [
+    [
+      "@babel/plugin-inject-polyfills",
+      {
+        "method": "usage-pure",
+        "providers": ["@@/corejs3"]
+      }
+    ]
+  ]
+}

packages/babel-polyfill-provider-corejs3/test/fixtures/usage-pure/modules-namespaced/output.mjs

@@ -0,0 +1,2 @@
+import * as bar from "bar";
+bar.map();