when landing you apply manual braking and the temps go up. If for some reason (usualy a bit heavy footed on them) the brake temps are high you need to cool them. Some aircraft have brake cooling fans that you switch on to help. But if you havent got these and you are on a short turn around or the pilot applies to much braking in the taxi to takeoff then you have high temps again. Most likely that the pilot flying could have been under line training and a bit to heavy on the feet but as you have read there could be a thousand reasons