1. Here's why

MP4 files from Lumion with a resolution of 2560x1440 (Quad HD) or 3840x2160 pixels (Ultra HD) might freeze or look strange when you view them in Windows Media Player on some PCs.

This is a known limitation in Windows Media Player as .MP4 files from Lumion are compressed with a very high bitrate to preserve the quality. Windows Media Player might not be fast enough to decode the video stream as it depends on the PC specifications (harddrive speed and CPU speed). In other words, it is unrelated to Lumion.

1.1: Please view the MP4 file in Windows 10 Films & TV, VLC or a different media player to resolve the problem. Alternatively, you can convert the MP4 file to a lower bitrate in 3rd party software and try to view it in Windows Media Player again.