Btw, i checked that this phenomenon happens on the same way with the official demo (scroll down on that page with an iphone, and the dim-blue parallax section at the bottom has zoomed background : https://sketchthemes.com/preview/?theme=70 ) I don’t know where to search to know where is the code line that produces this effect ! 🙁
If you check the mobile version of the website on a computer, it works as it should !
I found my mistake, i modified the source custom.js, hoping it would be less painful than adding another .js script with the additional parallax sections, but this made my original custom.js file not to work.
After restoring it and placing my script straight in the header under <?php wp_head(); ?> (i know it’s nasty, but that’s it!), it finally worked !
Hope i’ll help someone !
Did the https trick.
Works like a charm, thanks !