EVERYONE!!! I FOUND THE SOLUTION.
Since no one here seems to know the fix,
I have dedicated my entire day deciphering this code and found out the culprit were the vanilla props I added that are only available in GTA ONLINE. So if anyone else has the same problem, make sure to remove those online entities and remember to regenerate/rebuild your manifest.ymf. ALSO, if you insist on keeping those wacky props - just localize them by extracting from codewalker and literally adding them to your custom dlc. PEACEEEEE✌🏼
UPDATE!!
Any props that don't have collision (like the player can walk past it) will also cause your mlo to dissapear.
Atp. It's better to have custom props instead.