Mamiya 6 Shutter fires with light shield closed and lens question

I've got a new to me Mamiya 6 that I'm testing out. I noticed that I can often fire the shutter even if the light shield is closed. What I noted is that if I close the light shield and don't change the lens, I can fire the shutter. If I close the shield, and change the lens, then I can't fire the shutter until the light shield is opened.

I'm curious if anyone else has noted this with their Mamiya 6.

Also, I have a 150mm lens from KEH (excellent condition). I've noticed there is a slight squeak when focusing. Just in a specific spot. Is this anything to be concerned about?

Mine does not fire if the light shied is closed, before or after changing the lens. But I have the 6MF version of that camera.

I suspect there is something sticky (thickened grease/oil) in the switch that senses when your light shield is closed.

My lenses do not squeak.

okay. thanks for the reply. I'm going to send it in for a cla (partially paid for by the seller)