MP4 file bugges with timer action

I have added a MP4 loading animation to simulate that something is loading. I have a timer on the page, so after 3s, it should go to the next page automaticly (timer actiong). 

The issue is that its now working when i have the MP4 file playing. I have tried with:

• autoplay and looping
• autoplay
• not playing

The page wont transition if the file is autoplaying/looping. Its only when the MP4 is not active that the timer works.

Is this a bug or working as intended?