8th fret on my A string is buzzing?

So as i was playing around on my bass just now, i realized that the 8th fret of my A string has a high pitched buzzing sound. I know it's not fret buzz because i've raised my action and it has all gone away. This is a much higher pitched buzz that only happens on the 8th fret. It doesnt happen when i slap/pop it either.

It doesn't show up on recordings when i DI into the soundcard so i dont really have a way to let you listen to the noise.

Any ideas as to what this could be and how to fix it because it's extremely annoying. Thanks