Suspect Root Cause:1) Due to the presence of a small particle on the roller of the machine, it can cause repeated sharp dent during the coating process when OCA is pressed against the small particle.2) From the machine processing history, the machine was idling for 2 weeks prior to the coating run on 15 Oct. The long idling period may have caused particles to settle down on the rollers and it was found that the rollers was not wiped down prior to the coating run