I’m almost positive it’s a flashing/counter flashing failure on the roof above the soffit. It almost always is. One bad piece of flashing halfway up that roof could be it. Check that the gutters aren’t holding water though. If the siding detail behind the gutter endcap is bad, and the gutters endcap is leaking, that could do it. And remember water doesn’t always run downhill. That shit can and will go straight up a wall if the circumstances are right.