Halo around an object when rendering alpha

Hi Unrealers,

I am breaking my brains on this halo arround a talent (on a plane) when rendering in alpha. Both in EXR or PNG, path tracing or normal render. Tried lots of settings.

Anny idea what is coarsing this?

It’s a media source PNG file but it’s the same with a Mov on a plane with media player.

When I render out a Sphere in an alpha layer it doesn’t get a halo effect. So it’s only the plane with the media player as texture. (pixelstorm in this case as a plug-in)

Thanks in advanced…