For example I was searching for a song. I knew the name but couldn’t remember it and when I read its name I remembered! How can this be? I know it, I know that I know it, but my brain can’t recall it.
However, a different example would be smell or taste. Sometimes I can taste or smell something and recognise it but not know what it is or where it’s from. It’s so weird. Then eventually I remember and it’s almost a surprise how I didn’t get there faster.