After clicking on a link problem, the anchor will blink / blink ul-li

I opted for a Li-hover effect. The cursor moves to Anchor li, li moves down to simulate a click effect.
SEMrush

Every time I click, I see a flashing anchor background.

I googled Flash of the original content (or FOOC) and I add similar issues, but I can not find the right answer :(

I uploaded a snippet here http://www.test.kbk-legend.hr/index.php

Can anyone advise me how to prevent this?

Thank you for your help or suggestions!