Kodi 18 has issues with those files also in the U1 which has a different firmware. Playing issues with Xvid files has been long debated on Kodi Forum and not only for version 18, and obviously not Minix boxes related.
https://forum.kodi.tv/showthread.php?tid=328122
https://forum.kodi.tv/showthread.php?tid=178841
https://forum.kodi.tv/showthread.php?tid=18081
https://forum.kodi.tv/showthread.php?tid=229489
https://forum.kodi.tv/showthread.php?tid=337440
and so on and so on.
As stated before this is a Leia and latest official fw problem. works fine with earlier kodi. soo your links makes no sense. Its like i type "stuff" on google and copy paste the links here as a solution and so on. Read what people have problems with!