JPEG bug linked to video format

The HDMI issue is well documented, but it has secondary effects with my JPEG files…they display at a very low resolution, jagged lines are evident. When I see this, I go to the video settings and the output display is set to composite. If I change it to 1080p 60Hz to match my display & reboot, JPEGs then display properly. The thing is, I leave the Live Hub on 24/7, so it must be loosing HDMI handshake when I power down my display (Mits 3800 PJ), even though it routed thru a DENON 3310 receiver.