Mobile menu doesn't work only on iPad's

Hi,
The mobile menu doesn't work right on iPad. The submenus are always displayed, and the arrow for drop down is missing. On all other devices it works fine ..
Can you help me please?
Best regards
Ollie

Hi Olliek.
Thank you for using our product.
Please give me link your site and your account of the administrator via mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
I will check it for you soon

Dear Huyen,
I'd sent you an email with the datas.
Best regards
Ollie