62.4 DLI is plenty. You’ll want good intensity when (if) you reduce total hours of light a day as reducing total hours per day will reduce your DLI. A PPFD of ~800 is good. I run mine at 1,000 to 1,100.
Sounds like you are a little too intense on the light. If you go to HLG’s website and click on resources, and the calculators. First use the Lux to PPFD calculator. To obtain the actual PPFD from your 350R using the QB 648 board drop down. Then use the PPFD to DLI calculator to obtain the DLI at your light duration.
Here is a couple charts with the recommended DLI.
But all this is only good if you have accurate input numbers. The plant in your picture doesn’t look like it has been stressed by too much light. Sometimes I question the accuracy of my iPhone app. I don’t use the app during early veg, and just go by the plant’s stretch.
