Hello
This issue appears to be only present on some browsers. Unfortunately the only solution available at the moment is to hide the lines on smaller screen devices. To do so try adding the following to the Custom CSS field of your templates parameters...
@media only screen and (max-width: 767px) {
.module .module_header h3.mod_standard span::before,
.module_menu .module_header h3.mod_standard span::before,
.module .module_header h3.mod_standard span::after,
.module_menu .module_header h3.mod_standard span::after {
display: none;
}}
Ciarán