I´ve reached the Old Woods, and now i don´t see any beartraps anymore, unless i stepped onto them.
Those i place are fully visible, but those out in the wild, are they supposed to be invisible, or is it a bug, or...?

Are you sure they're invisible? They do blend in, but you should still be able to see if them if you look carefully.

Hmmmm, honestly I didn't notice any invisible bear traps. The ones I stepped in mostly are in the house where the guys with the mask are, that are kind of "hidden" but still perceptible, just that I needed to be quick.

Actually I didn't pay much attention to bear traps in the Old Woods either but I would say that I have seen those in all levels....