Late afternoon the leaves turn up, using a quantum board 288, dimmed to provide 7,000 lux. By morning the leaves will be flat and stay that way most of the day. Seems to get worse if I turn up the light? Thanks for any help.
Cotyledons will often reach/close upward when it gets too intense for them and then relax back after a lights out period. You might want to dial it back just a touch, but watch them as they'll likely be able to deal with progressively greater intensity as they develop. Often cotyledons will act like this, but the plants will simply adjust and be fine without reducing the light exposure. Symptoms to keep an eye on probably more important that what's happening with the cotyledons is if you see misshapen leaves once the first true leaves start to come in, such as incompletely formed or upward rolling leaf margins, or any spotting or necrosis indicating leaf burn.
Also might be worth confirming your LED's aren't too close to the sprout, as it's pretty easy to cause light OD with those boards by getting them too close.