The phrase "occasional scratch" means that something only happens or occurs every now and then, without being a regular or constant occurrence. Full definition
And while occasional scratching is normal for dogs and cats, the discomfort of dry or irritated skin can leave them scratching more than normal. (onegreenplanet.org)
The print is not flawless, but the occasional scratch or score mark is easily forgiven by the overall care shown to the film. (upcomingdiscs.com)
The 1.33:1 presentation is grainy and prone to the occasional scratch, but the high definition video uncovers fitting sharpness and detail. (dvdizzy.com)