Over the last few days I was doing various TCS tests. Around 1353568420 I noticed a large feature pop up in the DARM spectrum around 280Hz, it seemed to be coming and going, I was logged in remotely so unsure if this was happening a lot. Comparing to the lock today there are two smaller features in that area.

At the time I was just changing the H1:AWC-OM2_TSAMS_POWER_SET which is a thermal actuator and changes very slowly and also stepping the DARM offset H1:OMC-READOUT_X0_OFFSET. Whether that is related I'm not sure, I don't remember seeing such features whilst doing similar tests in the control room.