BMPCC did not record...solved

(See below for the reason. I found it while typing up all the details for this blog posting.
 The camera is actually working fine!)

I just had a problem with my Blackmagic Pocket Cinema Camera.
I thought I had recorded dozens of snippets of a 2 hour event.
Instead I ended up with 926KB or 640KB or 1 DNG-file (with no wav-file) per clip!
1 Frame!

What I did

Batteries in the BMPCC don't last long. So I had to switch the camera off whenever it was not in use and switch it back on just before recording (and hope whatever I wanted to record was still there when the camera was ready).
The audio recording with the Zoom H6 (that I used as a counter-weight at the back of my shoulder rig) simple ran all the time. I just canged the levels via the remote control on my left handle.

The symptoms

After half of the event was through, I noticed that the red "rec" indicator was glowing but the counter didn't move at all.
Since I can not watch my footage on the BMPCC, I had to go on and hope for the best.

The circumstances

I recorded on 2 different SD-cards. Both "Sandisk Extreme Pro 64GB" that I used before and that always performed flawlessly.
One formated by the camera as HFS+, the other formated by the camera das exFAT.

I used 2 lenses. a Panasonic 12-25mm f2.8 Power-OIS and a Panasonic 7-14mm.

I used 3 or 4 batteries.

I recorded just after the camera was switched on, after it had been running a minute and after it had recorded and was idle for a minute.

I recorded as ProRes422HQ, ProRes422 and as  RAW in 1920x1080p25.
ISO 1600 and 800, 180° shutter, 7000K white balance....
DAMN!!!
I think I found the problem. It was set to "time lapse interval 10min".
Just below the white balance setting.