Hello,
Here the issue : After setuping a camera and matinee to create a PNG image sequence. I have PNG’s File with a transparency I don’t want. The file attached explain that better than words.
So basically, how do I get rid off an unwanted alpha ?
Thank you all for the assistance ^^
Hi Kalth -
This appears to be a bug and I have entered a report with our engineers to look further into this issue, for reference UE-12996. As we investigate this issue further I will keep you informed here.
Thank you for your report -
Eric Ketchum
All right ! Thank you for the update !
Good hunting to the team 
