I have this feeling usually once a week or something, but usually credit it to vague memories, I have a very limited "space" I walk through to class, home or shops which means I go to places I have been before frequently, in each of those trips something seemingly remarkable or unique might happen and I will remember that briefly then it will be crystallized in my long-term memory. So the feeling of Deja Vu for me is attributed to seeing something similar to another time I walked past, but being unable to recall the memory as a thought, but knowing the scene as a intuitive feeling.
I do not remember the correct terminology for this specific memory event, but it is like the difference between information you can recall on the spot, and information you have to actively think forth. Deja Vu is essentially the first of those two, or so I have settled to believe so far anyhow.
Also, on the topic of memory glitch, memories are notoriously unreliable. But I am sure someone more skilled in the field could elaborate on that if you decide to look into it, or ask about.