Deciphering which COB LED used in a circuit
The LED's datasheet you linked to seems to indicate V[f] ~ 38V @ 150mA. So, when two of the LEDs are connected in parallel to a driver, and the driver tries to force 300mA through them, it would have to output about 38V, give or take. It seems the driver, trying to force 300mA to the LEDs, just maxes out at 37.5V (and probably below 300mA) because it cannot output more voltage than that (maybe limited by the input voltage it gets), or it achieves the 300mA by going 1.5V above the specified output voltage.

So I'd say it's not "electrically correct" to use a "300mA @ max. 36V" constant current driver in a setup which requires about 38V @ 300mA. It's probably constantly overloading the driver and will cause premature failure. (Would have to check the driver's datasheet if it is tolerable/recommended for the device to operate in this condition.)