Recently my car has this issue where the brake warning light turns on every now and then. It sometimes stays on when I release the handbrake, and it turns off shortly after; however, during the drive, the light reappears and disappears, and it happens inconsistently at random intervals. It does this for about 5 - 15 minutes, and then the light stays off for the rest of the day.
What I've noticed is that sometimes it disappears when I step on the brake, and comes back on when I go back onto the gas (but just sometimes

)... it happens mostly in the mornings, and may even have something to do with the temperature, perhaps?
For those who are wondering, my brake fluid has been topped and my pads are still at around 80%. I've been thinking of what may be causing it, but I have nothing. Anybody have any ideas?