I have lessons that after answering a question and getting to the feedback screen, lead to a blank view.php page. This occurs after hitting "Continue" from a correct answer feedback page-
Here is the debugging info:
Notice: Undefined offset: 2 in /usr/local/moodle/moodle-2.7.2/mod/videotracking/classes/media_player_html5video.php on line 63
Notice: Undefined offset: 3 in /usr/local/moodle/moodle-2.7.2/mod/videotracking/classes/media_player_html5video.php on line 63
Fatal error: Call to a member function get_id() on a non-object in /usr/local/moodle/moodle-2.7.2/mod/videotracking/classes/media_player_html5video.php on line 63
I figured this out. The issue was related to how I had the <video> tag condition if an HTML5 player was not available.