diff --git a/lib/command.ts b/lib/command.ts
index ff9da5b1b..42c0e570b 100644
--- a/lib/command.ts
+++ b/lib/command.ts
@@ -593,19 +593,20 @@ export class CommandInstance {
         positionalKeys.push(...parsed.aliases[key]);
       });
 
-      const defaults = yargs.getOptions().default;
       Object.keys(parsed.argv).forEach(key => {
         if (positionalKeys.includes(key)) {
           // any new aliases need to be placed in positionalMap, which
           // is used for validation.
           if (!positionalMap[key]) positionalMap[key] = parsed.argv[key];
           // Addresses: https://github.com/yargs/yargs/issues/1637
-          // If both positionals/options provided, no default was set,
+          // If both positionals/options provided,
+          // and no default or config values were set for that key,
           // and if at least one is an array: don't overwrite, combine.
           if (
-            !Object.hasOwnProperty.call(defaults, key) &&
-            Object.hasOwnProperty.call(argv, key) &&
-            Object.hasOwnProperty.call(parsed.argv, key) &&
+            !this.isInConfigs(yargs, key) &&
+            !this.isDefaulted(yargs, key) &&
+            Object.prototype.hasOwnProperty.call(argv, key) &&
+            Object.prototype.hasOwnProperty.call(parsed.argv, key) &&
             (Array.isArray(argv[key]) || Array.isArray(parsed.argv[key]))
           ) {
             argv[key] = ([] as string[]).concat(argv[key], parsed.argv[key]);
@@ -616,6 +617,27 @@ export class CommandInstance {
       });
     }
   }
+  // Check defaults for key (and camel case version of key)
+  isDefaulted(yargs: YargsInstance, key: string): boolean {
+    const {default: defaults} = yargs.getOptions();
+    return (
+      Object.prototype.hasOwnProperty.call(defaults, key) ||
+      Object.prototype.hasOwnProperty.call(
+        defaults,
+        this.shim.Parser.camelCase(key)
+      )
+    );
+  }
+  // Check each config for key (and camel case version of key)
+  isInConfigs(yargs: YargsInstance, key: string): boolean {
+    const {configObjects} = yargs.getOptions();
+    return (
+      configObjects.some(c => Object.prototype.hasOwnProperty.call(c, key)) ||
+      configObjects.some(c =>
+        Object.prototype.hasOwnProperty.call(c, this.shim.Parser.camelCase(key))
+      )
+    );
+  }
   runDefaultBuilderOn(yargs: YargsInstance): unknown | Promise<unknown> {
     if (!this.defaultCommand) return;
     if (this.shouldUpdateUsage(yargs)) {
diff --git a/lib/platform-shims/esm.mjs b/lib/platform-shims/esm.mjs
index 652d2e10a..7cddfdb45 100644
--- a/lib/platform-shims/esm.mjs
+++ b/lib/platform-shims/esm.mjs
@@ -22,7 +22,7 @@ try {
 } catch (e) {
   __dirname = process.cwd();
 }
-const mainFilename = __dirname.split('node_modules')[0];
+const mainFilename = __dirname.substring(0, __dirname.lastIndexOf('node_modules'));
 
 export default {
   assert: {
diff --git a/lib/yargs-factory.ts b/lib/yargs-factory.ts
index 279d8bcce..c3f88348f 100644
--- a/lib/yargs-factory.ts
+++ b/lib/yargs-factory.ts
@@ -871,7 +871,7 @@ export class YargsInstance {
   }
   locale(locale?: string): YargsInstance | string {
     argsert('[string]', [locale], arguments.length);
-    if (!locale) {
+    if (locale === undefined) {
       this[kGuessLocale]();
       return this.#shim.y18n.getLocale();
     }
diff --git a/locales/ru.json b/locales/ru.json
index 5f7f76810..d5c9e323b 100644
--- a/locales/ru.json
+++ b/locales/ru.json
@@ -42,5 +42,10 @@
   "Path to JSON config file": "Путь к файлу конфигурации JSON",
   "Show help": "Показать помощь",
   "Show version number": "Показать номер версии",
-  "Did you mean %s?": "Вы имели в виду %s?"
+  "Did you mean %s?": "Вы имели в виду %s?",
+  "Arguments %s and %s are mutually exclusive": "Аргументы %s и %s являются взаимоисключающими",
+  "Positionals:": "Позиционные аргументы:",
+  "command": "команда",
+  "deprecated": "устар.",
+  "deprecated: %s": "устар.: %s"
 }
diff --git a/test/command.cjs b/test/command.cjs
index 867f8f9b5..d5f94b8cb 100644
--- a/test/command.cjs
+++ b/test/command.cjs
@@ -264,6 +264,31 @@ describe('Command', () => {
         .parse('cmd apples cherries grapes');
     });
 
+    it('does not combine config values and provided values', () => {
+      yargs('foo bar baz qux')
+        .command({
+          command: '$0 <arg-1> [arg-2] [arg-3..]',
+          desc: 'default description',
+          builder: yargs =>
+            yargs
+              .option('arg-1', {type: 'string'})
+              .option('arg-2', {type: 'string'})
+              .option('arg-3', {type: 'string'})
+              .config({
+                arg2: 'bar',
+                arg3: ['baz', 'qux'],
+              }),
+          handler: argv => {
+            argv.arg1.should.equal('foo');
+            argv.arg2.should.equal('bar');
+            argv.arg3.should.deep.equal(['baz', 'qux']);
+            argv['arg-3'].should.deep.equal(['baz', 'qux']);
+          },
+        })
+        .strict()
+        .parse();
+    });
+
     it('does not overwrite options in argv if variadic and preserves falsy values', () => {
       yargs
         .command({
diff --git a/test/yargs.cjs b/test/yargs.cjs
index 2b4f81ca4..390f2359a 100644
--- a/test/yargs.cjs
+++ b/test/yargs.cjs
@@ -757,6 +757,38 @@ describe('yargs dsl tests', () => {
       r.logs.join(' ').should.match(/Parlay this here code of conduct/);
     });
 
+    // Addresses: https://github.com/yargs/yargs/issues/2178
+    it('does not enter infinite loop when locale is invalid', () => {
+      // Save env vars
+      const lcAll = process.env.LC_ALL;
+      const lcMessages = process.env.LC_MESSAGES;
+      const lang = process.env.LANG;
+      const language = process.env.LANGUAGE;
+      // Change
+      delete process.env.LC_ALL;
+      delete process.env.LC_MESSAGES;
+      process.env.LANG = '.UTF-8';
+      delete process.env.LANGUAGE;
+      try {
+        yargs
+          .command({
+            command: 'cmd1',
+            desc: 'cmd1 desc',
+            builder: () => {},
+            handler: _argv => {},
+          })
+          .parse();
+      } catch {
+        expect.fail();
+      } finally {
+        // Restore
+        process.env.LC_ALL = lcAll;
+        process.env.LC_MESSAGES = lcMessages;
+        process.env.LANG = lang;
+        process.env.LANGUAGE = language;
+      }
+    });
+
     describe('updateLocale', () => {
       it('allows you to override the default locale strings', () => {
         const r = checkOutput(() => {