MDDropdownMenu Position isn't working after second time

[einfall]

After second click on the Button the MDDropdownMenu Position isn't working (position="bottom").

from kivymd.app import MDApp
from kivy.lang import Builder
from kivymd.uix.menu import MDDropdownMenu
from kivy.utils import hex_colormap
from kivy.metrics import dp

from kivymd.uix.navigationbar import (
    MDNavigationBar,
    MDNavigationItem,
    MDNavigationItemLabel,
    MDNavigationItemIcon,
)

from kivymd.uix.button import (
    MDIconButton,
    MDButton,
    MDFabButton,
    MDButtonText,
    MDButtonIcon,
    MDExtendedFabButton,
    MDExtendedFabButtonIcon,
    MDExtendedFabButtonText,
)

KV = """
MDScreen:
    md_bg_color: self.theme_cls.backgroundColor

    MDBoxLayout:
        id: root_box
        orientation: "vertical"

        MDTopAppBar:
            id: appbar
            type: "small"
            pos_hint: {"center_x": 1.3}
    
            MDTopAppBarTrailingButtonContainer:
    
                MDActionTopAppBarButton:
                    icon: "menu"
                    #on_release: app.open_menu(self)
            
        ScrollView:
            MDBoxLayout:
                id: root_box
                orientation: "vertical"
                adaptive_height: True
                padding: 40
                spacing: 10
        
                MDButton:
                    id: button_menu
                    style: "filled"
                    radius: 6
                    theme_width: "Custom"
                    size_hint: (1, None)
                    on_release: app.button_menu(self)
            
                    MDButtonText:
                        #id: button_menu
                        text: "Open Menu"
                        pos_hint: {"center_x": .5, "center_y": .5}
                        font_size: '60dp'

                MDButton:
                    id: button_menu2
                    style: "filled"
                    radius: 6
                    theme_width: "Custom"
                    size_hint: (1, None)
                    on_release: app.button_menu2(self)
            
                    MDButtonText:
                        #id: button_menu
                        text: "Open Menu"
                        pos_hint: {"center_x": .5, "center_y": .5}
                        font_size: '60dp'

"""

from kivy.core.window import Window
Window.size = (400, 600)
Window.top = 150
Window.left = 850

class Test(MDApp):
    def build(self):
        return Builder.load_string(KV)

    def on_start(self):
        super().on_start()
        available_palettes = [
            name_color.capitalize() for name_color in hex_colormap.keys()
        ]

        menu_items = []
        for name_palette in available_palettes:
            menu_items.append(
                {
                    "text": name_palette,
                    #"on_release": lambda x=name_palette: self.switch_palette(x),
                }
            )
        self.menu_down = MDDropdownMenu(
            caller=self.root.ids.button_menu,
            items=menu_items,
            max_height=dp(600),
            position="bottom",
            ver_growth="down",
        )

        self.menu_down2 = MDDropdownMenu(
            caller=self.root.ids.button_menu2,
            items=menu_items,
            position="bottom",
            ver_growth="down",
        )

    def button_menu(self, instance_from_menu):
        self.menu_down.open()

    def button_menu2(self, instance_from_menu):
        self.menu_down2.open()


Test().run()

https://github.com/kivymd/KivyMD/assets/3679001/12ab3264-abec-4d18-bc5c-e260bb9fa3a0