At 21:29:20 today, the number of bunches in SASE1 was increased from 1 to 352 without intervention of the SPB/SFX shift crew. 30 seconds later, the number of bunches was reduced to 1, again without intervention from the SPB/SFX shift crew (see attachments 1 and 2).

We were in the middle of a measurement at that time and the sudden increase from 10 mW to 3.5 W average power resulted in the destruction of the sample we were using.

AGIPD and JUNGFRAU are safe and were not at risk at the time of the incident, but this is merely by luck.

The origin of the change in number of bunches is unclear to us and needs to be investigated. It goes without saying that this is extremely dangerous for equipment and the damages could have been even worse.