Correct me if I'm wrong, but it sounds like you are happy with the video exported out from Photoshop but are unhappy with the preview image of the video displayed by other programs and/or your operating system.
Upon inspecting the exported video in Premiere, it's actually :15 longer than it should be.
I'ts 5 seconds in Photoshop, but the exported mp4 is 5:15.
And my animation has that part flying up from frame one and the exported mp4 has one second of stillness before it animates. Then :15 of stillness at the end instead of the one second I designated in Photoshop.