Why dark theme doesn't work correctly in flutter?

I’m trying to build custom two themes light and dark, but it doesn’t work perfectly when I switch to dark or light themes. I get strange colors as I will attach from an emulator screenshot but when I restart the app it works very well.

This is my main screen:

ThemeController themecontroller = Get.put(ThemeController());
return GetMaterialApp(
    title: 'where to go',
    debugShowCheckedModeBanner: false,
    translations: Messages(),
    locale: mycontroller.initlang,
    theme: themecontroller.themedata
        ? Themes.customDarkTheme
        : Themes.customLightTheme,
    darkTheme: Themes.customDarkTheme,
    home: const SplashScreen());

and this is my custom theme. I know it’s messy, but still learning the idea.

class Themes {
  static ThemeData customLightTheme = ThemeData(
      brightness: Brightness.light,
      colorScheme: ColorScheme.light(
        background: Colors.white,
        primary: Colors.white,
        onPrimary: Colors.grey[600]!,
        secondary: Colors.white,
        onSecondary: Colors.grey[600]!,
        surface: Colors.white,
        onSurface: Colors.deepPurple,
        tertiary: Colors.black,
        onTertiary: const Color.fromRGBO(96, 102, 214, 1),
      ));

  static ThemeData customDarkTheme = ThemeData(
      brightness: Brightness.dark,
      colorScheme: ColorScheme.dark(
        background: Colors.black,
        primary: Colors.white.withOpacity(0.87),
        onPrimary: Colors.white.withOpacity(0.60),
        secondary: Colors.grey[800]!,
        onSecondary: Colors.white.withOpacity(0.38),
        surface: const Color(0xff121212),
        onSurface: Colors.white.withOpacity(0.87),
        tertiary: Colors.white.withOpacity(0.80),
        onTertiary: const Color(0xff121212),
      ));
}

and that’s my setting screen all screens I made with the same way

  Widget build(BuildContext context) {
    return Scaffold(
          appBar: AppBar(
              leading: IconButton(
                onPressed: () {
                  Get.off(const HomePage());
                },
                icon: const Icon(
                  Icons.arrow_back_outlined,
                ),
              ),
              iconTheme: const IconThemeData(color: Colors.white),
              title: Text(
                'Settings'.tr,
                style: TextStyle(
                    fontSize: 25.0,
                    fontWeight: FontWeight.bold,
                    color: Theme.of(context).colorScheme.primary),
              ),
              flexibleSpace: Container(
                decoration: Get.isDarkMode
                    ? const BoxDecoration(color: Color(0xff121212))
                    : const BoxDecoration(
                        gradient: LinearGradient(
                            begin: Alignment.topLeft,
                            end: Alignment.bottomRight,
                            colors: <Color>[
                              Color.fromRGBO(78, 84, 200, 1.0),
                              Color.fromRGBO(127, 133, 239, 1.0),
                            ]),
                      ),
              )),
          body: Container(
            padding: const EdgeInsets.all(8.0),
            child: ListView(
              children: [
                const SizedBox(
                  height: 40.0,
                ),
                Row(
                  children: [
                    Icon(
                      Icons.person,
                      color: Theme.of(context).colorScheme.onSurface,
                    ),
                    const SizedBox(
                      width: 10.0,
                    ),
                    Text('Account'.tr,
                        style: TextStyle(
                            color: Theme.of(context).colorScheme.tertiary,
                            fontSize: 20.0,
                            fontWeight: FontWeight.bold))
                  ],
                ),
                const Divider(
                  height: 20.0,
                  thickness: 1.0,
                ),
                const SizedBox(
                  height: 10.0,
                ),
                buildAccountOption(context, "Change Password".tr, 0),
                buildAccountOption(context, "Language".tr, 1),
                buildAccountOption(context, "Privacy and Security".tr, 2),
                buildAccountOption(context, "Delete Account".tr, 3),
                buildAccountOption(context, "Logout".tr, 4),
                const SizedBox(
                  height: 40.0,
                ),
                Row(
                  children: [
                    Icon(
                      Icons.theater_comedy,
                      color: Theme.of(context).colorScheme.onSurface,
                    ),
                    const SizedBox(
                      width: 10.0,
                    ),
                    Text('Theme',
                        style: TextStyle(
                            fontSize: 20.0,
                            fontWeight: FontWeight.bold,
                            color: Theme.of(context).colorScheme.tertiary))
                  ],
                ),
                const Divider(
                  height: 20.0,
                  thickness: 1.0,
                ),
                const SizedBox(
                  height: 10.0,
                ),
                buildNotificationOption2(
                  "Theme Dark",
                  valNotify1,
                  onChangedFunc1,
                ),
/*                 buildNotificationOption1(),
                const SizedBox(
                  height: 10.0,
                ),
                Center(
                  child: OutlinedButton(
                    style: OutlinedButton.styleFrom(
                        padding: const EdgeInsets.symmetric(horizontal: 40.0),
                        shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(20.0),
                        )),
                    onPressed: () {},
                    child: const Text(
                      "Save",
                      style: TextStyle(
                          fontSize: 16.0,
                          color: Colors.black,
                          letterSpacing: 2.2),
                    ),
                  ),
                ) */
              ],
            ),
          ),
        );
  }

and that’s my screenshot images after applying the theme and restarting the emulator