Only reverse is ever straight cut in any normal gearbox. Straight cut gears are too noisy for 90% of drivers.
3rd is
usually the gear broken in F and G boxes, not 1st/2nd. 3rd is more or less in the middle of the box, and as the box casing flexes, the teeth of 3rd can move apart more than 1st/2nd and all the force is put on the edge of the teeth, rather than the whole tooth.
Bourbon is just weird