you were worried about slow growth in a recent question, right? probably related. give it less light and it'll recover from whatever funk it is in. it may not happen overnight.
use spec sheet of your light to find umol/s produced. divide that value by your area in Meters Squared, then referenec that value on a Daily Light Integral (DLI chart) with hours of use. Shoot for 35ish DLI to be safe, since they are likely light-stunted a bit. you can try to push a bit higher once they start growing normally again -- trial and error after that to find that point where no negative ramfications occur and maximize what you can give.
35-40 dLI will be the most you can give with ambient co2. do note that some damage takes weeks to be visible. so even if it starts to grow okay and 2 weeks from now you find some burnt spots or whateve ron top leaves or any bleaching of top colas, you may need to reduce further. when close to "max" it's easy to cause slow daage over long period of time. it's a good and bad thing.. good because you are super close to optimal and easy to adjust to slow moving problems with a small change.