Opacity overlay flickering during transition in Safari

I am looking at the demo site:
https://themes.ishyoboy.com/kopy/

The second entry on the blog section (the one that begins “Our prime purpose in this life”) has a strange behaviour. The opacity overlay disappears while the image is zooming, and then reappears when the zooming has finished.

The behaviour is perfect in Firefox. Seems to be an issue only in Safari.