add the following snippet in your child theme functions.php or wplms customizer -> wplms_customizer.php

PHP Code:

 

 

   add_filter('wplms_unit_mark_complete','wplms_unit_miniumum_time',1,3);  
function wplms_unit_miniumum_time($mark_unit_html,$unit_id,$course_id){
				 
					$unit_time = get_post_meta($unit_id,'vibe_duration',true);
					$unit_duration_parameter = apply_filters('vibe_unit_duration_parameter',60);
					 
					$units = bp_course_get_curriculum_units($course_id);
					$key = array_search($unit_id,$units);
					if($key > 0){
						$pre_unit_completion_time = get_user_meta($user_id,$units[$key-1],true);
						 
						$unit_time_spent= ($pre_unit_completion_time+$unit_duration_parameter*$unit_time) - time();
					 
						if($unit_time_spent > 0 ){ // Minimum time remaining
							      echo "<script>jQuery(document).ready(function(){
										$('#mark-complete').addClass('disabled');
										setTimeout(function(){
											$('#mark-complete').removeClass('disabled');
										}, $unit_time_spent);
										});</script>";  
						 }
					}
					return $mark_unit_html;
				}