Still image is strobing / blinking after export

[VivalaOpium]

Hi!

I have a file in the format 1080x3840px which contains some still images and graphic, with a layer of snow under and over the image. I encounter a problem after I export, the still images strobes / blinks every third second or so. 

I have tried to change some export setting and settings for the snow, but the problem still persists. I suspect it has something to do with the format in combination with the snow, because when I ran some tests with 1920x1080px the problem is gone. I have uploaded some examples of the problem at this location: 

https://we.tl/t-Ubrt5D5bt9 

Comp1.mp4 is the correct format and the snow I am currently wanting to use, the problem is visible.

Comp1_1.mp4 is the 1920x1080 format, where I don't see the problem.

Comp1_2.mp4 I tried to stretch the image so you maybe see the problem clearer.

Comp1_3.mp4 is without the snow, and the problem is gone.

Have anyone else encountered something similar, and do you have a solution to fix this?

[VivalaOpium]

Forgot to add that I'm using the most recent version of After Effects, and I'm on a Mac.

[doncvoila]

I have a similar probleme, but with my rushes. All my render have a very light blinking. 
I'm on a brand new Mac Studio Ultra. I tryed to render on after effect or media encoder, in the last 3 versions ( 2023-2022-2020) and have teh same problem.  And if I send the render on my old MacPro (2010) the render are ok. 
Someone got an idea ?

[Rick Gerard]

You have created an extremely odd comp size that will not play well on any standard media player. That may have something to do with the problem. I can't really see anything wrong. I watched both problem videos several times, followed snowflakes, and carefully observed the images. Nothing jumps out as a problem except the frame size. There is no way to get the video to 100% scale on a monitor because it's way too tall. Maybe what you are seeing is just a display error caused by your media player having problems resizing the video.

[VivalaOpium]

That's strange, I got some help elsewere, and they were able to observe the problem. Nevertheless, when I exported the files with a higher quality / bit rate the problem disappeared. 

Also I'm aware that it's a odd format, but these are for some special large "live banner" screens that as far as I know actually have this resolution. 

Thanks anyway!