Normals are randomly flipped by roblox when importing from blender

[Vmena]

I’m importing this castle model from blender:

But when it’s imported into roblox, some of the objects randomly have their normals flipped with no explanation.

But looking back in blender, you can see that all of the normals are facing the correct direction and are not inverted:

I have no idea what could be causing this, it may be a bug with roblox importing?
Does anyone know anything that may be causing this? (I am using .fbx file format.)

[Vmena]

After importing from .obj instead of .fbx, it seems that the normals are no longer flipped. This is either a problem with how blender exports .fbx or how roblox imports it, but the problem isn’t occurring anymore since I used .obj