Can confirm. You obviously know it's a cup, you know you know the word cup, the word cup feels right on the edge of your tongue, but for the life of you, you cannot say cup.

I have the same issue due to brain damage. The way people react is ridiculous. I'm just as intelligent as I always was, I still am a masters educated historian even if I can't fucking say cup sometimes. But everyone thinks you're dumb because of it. Which is well, dumb.