diff --git a/packages/webpack-cli/lib/groups/resolveConfig.js b/packages/webpack-cli/lib/groups/resolveConfig.js
index 18d3a5cbca4..d115b067b2c 100644
--- a/packages/webpack-cli/lib/groups/resolveConfig.js
+++ b/packages/webpack-cli/lib/groups/resolveConfig.js
@@ -156,9 +156,9 @@ const finalize = async (moduleObj, args) => {
     const isMultiCompilerMode = Array.isArray(config);
     const rawConfigs = isMultiCompilerMode ? config : [config];
 
-    let isFunctionalConfig = false;
+    let configs = [];
 
-    let configs = await Promise.all(
+    await Promise.all(
         rawConfigs.map(async (rawConfig) => {
             const isPromise = typeof rawConfig.then === 'function';
 
@@ -168,20 +168,26 @@ const finalize = async (moduleObj, args) => {
 
             // `Promise` may return `Function`
             if (typeof rawConfig === 'function') {
-                isFunctionalConfig = true;
                 // when config is a function, pass the env from args to the config function
                 rawConfig = await rawConfig(env, args);
             }
 
             return rawConfig;
         }),
-    );
+    ).then((allConfigs) => {
+        allConfigs.map((singleConfig) => {
+            if (Array.isArray(singleConfig)) {
+                singleConfig.map((conf) => configs.push(conf));
+            } else {
+                configs.push(singleConfig);
+            }
+        });
+    });
 
     if (configName) {
         const foundConfigNames = [];
-        const configsToFilter = Array.isArray[configs[0]] ? configs[0] : configs;
 
-        configs = configsToFilter.filter((options) => {
+        configs = configs.filter((options) => {
             const found = configName.includes(options.name);
 
             if (found) {
@@ -208,7 +214,7 @@ const finalize = async (moduleObj, args) => {
         process.exit(2);
     }
 
-    newOptionsObject['options'] = isMultiCompilerMode || isFunctionalConfig ? configs : configs[0];
+    newOptionsObject['options'] = isMultiCompilerMode || Array.isArray(configs) ? configs : configs[0];
 
     return newOptionsObject;
 };