Background image after upgrade Hugo Academics 4.7 to 4.8

When I upgraded Hugo Academic from 4.7 to 4.8 home page widget background image is not shown and generated html is different. Source repo:

Generated html in 4.7

<section id="email_skupina" class="home-section wg-blank dark bg-image parallax" style="background-image:linear-gradient(rgba(0,0,0,0.6),rgba(0,0,0,0.6)),url('');background-position:50%;padding:20px 0">

vs. 4.8

<section id="email_skupina" class="home-section wg-blank   ">

Any help appreciated.
Might be loosly related to the issue:

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