Mobile menu disappears when touched (iphone)

I have a problem with a website that is under Virtue theme. https://www.loviisankehohuoltamo.fi when i go to it on my phone the mobile menu is available but after one touch it reveals the menu for only a second. This is highly problematic. I updated the Virtue theme just now. I updated everything that needed updating and it didn’t change. It used to be ok. But today a client informed me of the problem.

I also tried “turning it off and on again” by taking the mobile menu down and opening it again. No change. ??

Heeeeeelp

I’m using iPhone 5s (safari).