Road Atlanta 2021 Temp Spike

Water temp max 287F.  Rise & drop with rpm, lagging.
Oil temp max 226F
Coolant pressure (normal 18-24psi), 18-37psi
No steam, no sign of leak.
Radiator was cool to the touch minutes after race end.
Reservoir empty.
No issues detected from car.  It drove fine, drove into trailer at end of race, and into garage once home.
Tested thermostat, passed.No apparent obstructions in radiator.  
Pulled water pump, intact and good.
Pulled head, gasket has no visible signs of breakage/crack.  Odd wave between 1&2 in the gasket.