Why is the video feed split into multiple short files on my MicroSD card instead of one long continuous video?

This is normal. The monitor saves video in shorter clips to help protect your recordings if power is interrupted.

Full Answer:
The monitor is designed to save video in shorter clips instead of one long video file.
This helps protect your recordings. If the power cable is unplugged or the vehicle turns off unexpectedly, only the current short clip may be affected instead of one large video file.
You can choose the clip length in Monitor Settings > Loop Record. Depending on your setting, videos can be saved in 1, 3, or 5-minute clips.
When you view the files later, they will appear in order by time.