Folder within Finder has wrong icon, white 'unknown file ' type icon

just been noticing random folders and their child folders all have the wrong folder icon within Finder.

This is not in the dock or the side bar, within the actual Finder main pane.

Instead of the normal blue folder Icon I have this white icon that looks like a page with a corner turned down at top left.

All Child folders of that parent folder display the same wrong white icon too.

I have never messed with out done any folder style customisation or tinkered with icons at all.

Folder contents are all correct (FLAC Music files ) and this is only a minor annoyance, ..just would be nice to fix it.

Not done any recent software changes or upgrades..