Submenu doubles up

I got a issue on my site where the sub menu double up - shows two times. How do i fix this?

Ex.:
submenu for mainmenu Fiskeutvalget

Site:
www.melhusjff.org

Have a look at
Joomla back end admin
Extensions > Module Manager >
put menu in the filter and click Go
look to see if there are two modules published to mj_iphone_middle

Hope this helps.

Yes I have two modules published in this position because i use menus both from my top menu and main menu on the front page.

If i change the bosition for my top menu to ex. middle2 then the sub menus also shows in both middle and middel2 positions.

The sub menus belongs to the Main Menu module.

I have tried to reproduce the problem using the demo Joomla site but I could not.
Can I just ask what the settings are on the site?

Module Type: mod_mj_menu
Position: mj_iphone_middle
Menu assignment
Menus: all (*)
Module Parameters
menu name mainmenu
layout auto
Type submenu only
Advanced parameters (none)
Other Parameters
Format text only

Thanks.