Locate the Style tab of the section > Shape Divider setting > edit or disable the Top and Bottom divider:
Please check these guides for further information:
Guide to Vamtam Elementor Builder
To hide the shape divider, add the code below to Customize > Additional CSS
.elementor-widget-posts .elementor-post .elementor-post__thumbnail .vamtam-shape { display: none !important; }
VamTam Elementor Themes: How to add custom CSS / PHP code or modify the theme code