"Only reason I bring it up is because a guy I work with bought the same truck a day before I did, we travel the same distance to work, but his does not make this sound."

Now that's odd - same conditions/weather/commute etc - I'd expect them to behave the same.

Anyone wanna speculate what could be different?

Mine does that frequently, as have many vehicles I've owned so I don't really pay much attention to it.