Prev–Next Post navigation not working by using full width easyslider

you can deactivate the fullwidth/fullscreen slider check by filter: avf_post_nav_settings former: avia_post_nav_settings
if you only like to have that on posts/portfolio put this to your child-theme functions.php

function my_avf_post_nav_settings( array $settings ){
	if( ! in_array( $settings['type'], array( 'post', 'portfolio' ) ) ){
		$settings['is_fullwidth'] = false;
		return $settings;
	}
}
add_filter( 'avf_post_nav_settings', 'my_avf_post_nav_settings', 10, 1 );

maybe it will be necessary to shift those post-nav arrows ( especially on full-screen sliders )
then it maybe better to have them in absolute position

if you got no child-theme –
where did you place that snippet?

try it just after that comment – but before the : require_once( 'functions-enfold.php' );

for both then try:

function my_avf_post_nav_settings( array $settings ){
     // yes you can add here other post types like product or other cpt
  if( ! in_array( $settings['type'], array( 'post', 'portfolio' ) ) ){
    $settings['same_category'] = true;
    $settings['is_fullwidth'] = false;
    return $settings;
  }
}
add_filter( 'avf_post_nav_settings', 'my_avf_post_nav_settings', 10, 1 );

but without child-theme you had to do that each time enfold parent is updating.