There may be a few people in this world who can answer your question as written. You will increase you chances of getting an answer if you provide some details and background information. We are not mind readers.
Have you contacted the manufacturer and asked for help?
From their website, under "processing information": Care should be taken when using valve gates as to avoid high shear during the injection process, as this may cause silver streaking in the molded part. Hot runners and valve gating are typically not suggested for use when molding precision lens type parts.
Did you fix this?
Never heard of too big a gate. Too small, definitely.
Suggest you try some sort shots.
If it's still there, reduce hold time or pressure. You may be pushing cold material into the cavity. COC is not like an ordinary poleolefin.
Politicians like to panic, they need activity. It is their substitute for achievement.
