They make a lot of internal parts. There are specs for them the parts should meet. Inspection is supposed to insure the parts are as close to identical as possible but things vary - within the specs.
Then all these parts, with small variations in dimensions, get put together to make the pistol. Some parts fit/work together better than other parts.
My P07 DUTY (plastic frame) came out of the box with around a 3.25 lb. SA trigger pull and around 8.25 DA trigger pull. After a few years of shooting and installation of some CGW springs the SA is right at 3 lbs. now,
Congratulation on getting a pistol with a nice trigger right out of the box. Not everyone does.