I was following this topic. My KLEO 2.3.1 deals with similar display problems for self hosted videos.
Basically its the height of .mejs-container that spans incorrectly, I think.
In IExplorer, the container does not respect the available width on the single page with sidebar if a poster is set. I have created a poster with exact dimensions taken from the mp4 file: the poster breaks into the sidebar (probably the “stretching” parameter would help)
Question: Do you add the indicated fixes from this thread into the next theme update?
Some screenshots:
