S5 Strange behavior while turned off...

I've bought an S5 Pro recently. It shoots well, everything seems to work fine, but it behaves strangely when turned off.

After I turn it off with a CF card inside, it begins flashing it CF activity LED. One short flash in 2 seconds... It does so for some time (I am not sure how much exactly, but more then 20 mins and less then 3 hours). Then this strange behavior stops.

While this led flashing does on, camera drains it's battery. Yesterday I've gave it a fully charged one and turned it off and today it has 3 of 5 marks of charge.

Anyone knows what is it all about?

Camera firmware - 1.09 and 1.12 (same happens with both), batteries are original NP-150 from Fuji, not new but nod dead, like 20% usage.

Strange, have you tried a different CF card?

Also, was the card formatted in the camera, and then again after you've put it in another device to get the photos off? I seem to recall that Macs, for example, write additional data to the card which might cause problems. I use an app on my MacBook to wipe those files and eject the SD cards I use with my cameras.

Yep I've tried 2 different cards. One from the time of S5, a 45x 1GB card and one I've bought yesterday - 133x 16Gb Transcend.

Bith Cards were formatted in camera or course. I don;t have any other devices that use CF cards. Lucky me I have a cardreader for that ancient format lol.

Maybe try a full reset of the camera if you haven't already. I have no idea if that's something that is good to do with the S5 when you've upgraded or downgraded firmware but it's worth a shot.

Returning to the point about extraneous data written by some computers - did you format the card again in the camera after you had used the card reader?

I will try all that, thanks!