OVF and LV metering
Did you cover the viewfinder when doing OVF shooting, or at least have your face up to it? If not, that can throw off the metering.
First thing I was thinking, not covering the viewfinder happens easily when using a tripod. Noticed it when shooting landscapes with a timer. Still it seems strange and maybe it is only an impression.
Active outdoor photographer, trying to become better, studying user experience.