Production & Technical Aid

[Hypex]

Stems often are not mastered, like the final track because it would take more time to do each track. Maybe that's why you hear a difference.

Yes that would likely account for it as well. I've noticed most stems do have the FX added so rarely ever dry. But given stems are a mix down that would come as no surprise. I prefer them wet even if it can make it hard to cut at breaks with a reverb tail. Some stems, like RB ones, do tend to be 6dB over. Other ones can be too low.

At the end of the day, while mixing and mastering it, you need to remix and remaster it. :-)