Should a canted bay window roof have soffit?

We have a two story house are repairing some leaks above the canted bay window in our living room on the first floor. We got the leak stopped, pulled out the ceiling and affected insulation. After seeing the plastic on the ceiling breathing from the wind afterwards, we started to wonder if the roofing over the window is actually supposed to have soffit. It would technically be venting the space between the first and second floor where some of my air ducts run. Has me wondering if that’s why my 2nd story floor plywood creaks now. I always thought soffit was to allow air to be pulled in and exhausted through the ridge vent, but this spot has no other exit.

Is it normal for it to be vented? Our house was a flip so there’s some questionable work by the flipper.