Try using the in5 Video widget. With the video selected, go to the Video widget (in5 > Interactive Widgets > Video) and deselect Auto Rewind.
Auto Rewind is already deselected for all videos. And the videos work fine in iOS after version 12. Don't even know if this is a big deal but I found the anomaly and thought I'd ask. I have no idea how many in my audience may still be using iOS 12 or less. But in case they are, I thought I might need to have some special code to append for those cases so the website doesn't appear broken for those users. Does that seem like a logical next step?
Thanks for checking the Auto Rewind setting in the in5 Video widget.
I did see that there was previously an issue if the video has a poster image set. If the video has a poster image, then after the video is finished, the poster image is applied on top on the video. Try setting the poster to None in the Media panel (Window > Interactive > Media).
For a workaround, you could use the End Action feature in the in5 Video widget. You would need to put the video and the final frame image in separate object states of a multi-state object. The 1st state would have the video set to autoplay, and the 2nd state would have the image. Select the video, and in the Video widget, set End Action to Go to State set to go to the 2nd state that contains the image.