I am testing out a Canon av1, which seems to work last week, but today she has a mind of her own. The shutter doesn't fire when I like it to fire. It almost seems like the camera needs to recharge and then the shutter reacts.
The battery check says < 30 so could this be the cause??
I had the same trouble with an Oly OMPC. They both use an electromagnetic shutter release and the Oly had the slightest bit of oil on the electromagnet's contacts which caused the shutter to release just about any time within 20 seconds after pressing the release button, but never immediate. Cleaned the surfaces on the electromagnet and all is well.