SJ5000x, Loop Recording set to 3 Minutes, the files overlap for 1 second while on my SJ4000 the files line up exactly correct. This would appear to be a bug. I have since turned off loop recording to avoid the jump in the video every 3 minutes and the need to cut every video by 59 frames and overlap the two videos by 1 frame to prevent the audio from having a 1 frame dropout.
Figured out a workaround (1080p, 60 fps). 1) Navigate to 00;59;00 on the next clip, cut and delete. It should match up with the previous; 2) Another options is go to the end of the first clip at 2:59:59, cut and delete the remaining portion of the clip. Then cut 1 frame from the next clip. It will match up correctly. I see that each 3 minute clip ends up being 3:01:01 long. Version: 1.5.5-S, Aug 21, 2018 Nothing further available and this problem has not been fixed.