Media Players / Media Textures get out of sync after a while

Hello together,

I have a question regarding multiple Media Players / Media Textures. I have a huge “Screen” where I need to play a very large Video Sequence (24.000 x 3000 px) and since Unreal doesn’t seem to like videos that are larger than 4k in width, I decided to split the Screen-Geometry and also the video itself into 6 pieces (resulting in 6 videos 4000 x 3000 px each). The video itself is a seamless 30-second loop.
This setup works perfectly fine, but just for about 5-10 minutes - after that, the parts start to get slightly asynchronous.

Is there just some checkbox I have to toggle, or some other obvious thing I haven’t thought about?

I’m using Unreal Engine 4.23.4 (I can’t upgrade because of another software dependency down the line).

Thank you in advance.

Best regards,