When auto-sensor-cleaning is switched off, the card LED blinks a few times on startup and the goes on steadily. ON/OFF switch does not turn off card LED. Must remove battery.
In this case taking a photo causes Err 80 and shutter can be closed (reset) only by re-inserting battery.
When auto-sensor-cleaning is switched on, everything seems ok.
Another thing, not sure if related, is that magic zoom flickers. The flicker is much less severe when recording a video than when not recording.