Library / Folders icons

Hi everyone

I've moved to a new computer and while importing my photographs from an external ssd, all of them are imported ok, but in the module Library / Folders, some of the folders appear with a differetn icon, a triangle that point towards the name of the folder or when you click in the folder, then, the triangle points downwards. On most of the folders the triangles shows a solid withe color, but in some of them it's subdued or like a matrix of dots. Does somebody know why is this happening? I've tried to sinchronize such folders bur everyting remains the same. I have the latest Lightroom Classic version

I've attached an image of the folders

Thaks so much

Carlos