Wow, this reminds me that i wanted to open a thread about that as well.
I'm not at home right now, so i'm not sure if my desoldering station is the same model, but it seems i have the same phenomenon happening.
Plugged in, switched off, every few minutes i see a very short flash from the display, and i hear a sound coming from the station.
I'm in germany,so i do not have polarized plugs, could that be an issue? I have not yet tried to reverse the plug.
It works fine when i use it.