Could you please tell us where exactly you see this dotted triangle?
In most situations, if you hold your mouse over the icon, a message will appear. What is that message?
Can you show us a screen capture of this triangle?
The 'Solid" triangles indicate that there are sub-folders below the visible folder while the "Dotted" or "Greyed-out" triangles show that there are no sub-folders.
No action is required on your part to normalize them, it is just a visualization hint.
This is very kind of you.
I thank you very much,