New plant leaves has mark on it need help

To me it looks like damage caused by the leaves hitting either the side of the pot or the soil surface, most probably at night when the leaves are lowered and when the fan blows on them, causing them to rub and then leading to the damage you see here. Without many more detail, this is my best suggestion that I can interpret from one picture. This is not an issue caused by temps and 25 is not hot, 45 deg C is! Hope this helps, Organoman.