HTML5 - video and animation trigger (self time based animation)

Hi,  i have this annoying issue.

I create a project that include a video with progessive download in TOC.

The video (mp4) duration of each slide is less than 5 minutes and in the timeline there are inserted some image with animation on the stage.

All is published only in html5.

When the project is published on the LMS all work fine until the user open another web page.

When the slide finish and the user is viewing another web page, when he returs the video is paused (like is finished) while the animation continue from the last viewed from the user and only after the user can go to the next slide.

Is like the slide have to finish the animation that the user "skipped" because was viewing other.

Some ideas?

(captivate 2017: tested with chrome and edge)

Interesting fact.

I tested all on scorm cloud: the error is not showing only if is setted to open in a new window