no submit button and no grades in Interactive Video

Hi,

I hope someone helps me out with this. 

1. I read a lot of other threads on this issue in this forum. I tried for two hours to fix and came to conclusion so far that i'd rather not use this type of content again. I am writing as I am interested to know what the problem was. 
2. Platform and version number.: Moodle 3.5.8
3. Mobile or Desktop: both
4. Browser: Chrome, Firefox, Safari etc: tried Chrome and Safari
5. H5P plugin version: 1.19.1
6. H5P content type and version (if a content type was used), and a sample URL or attached H5P.: Interactive video
7. Any browser console errors
8. Any PHP errors
9. Screenshots if it's a visual problem
10. Any recent changes to the environment (new plugins/modules, updates, configuration changes etc.): no
11. Any recent changes to the browser you're using (new extensions, updates etc.): no

I created two Interactive Video tasks and added a summary task. I clicked on a star and added submission button. 

Problem 1: Video lasts 6:36 but the submit screen shows 6:35 option. I added and I see in the editing mode a kind of line at the end of the navigation bar. I clicked 'save and display' and tried playing the video, as well as answering the questions. I see my score but no submit screen pops up and no grades as a result. 

Problem 2: Trying to figure out what the problem is and also creating another similar task, starting the browser again, I managed to see a submit button with the timer 6:36 (the end of the video). I  clicked 'save and display', watched the video from start to the very end and did the summary task. I see my score but no submit button and no grades as a result.