For me this happens because of armed speed brakes after Aircraft Power up and once disarmed the short alarm disappears. I have it only on A320/321 after selecting Cold&Dark state. I think Active Sky has nothing to do with this and it seems to be a conflict somewhere (by the way I have the speedbrake arm toggle assigned to a button in FSUICP registered version).
I had the same problem once and I uninstalled GSX completely (as described on FSDT support forum) and re-installed again and all was fixed. Sometimes the new Updater messes things up and I still prefer to download and install the Standalone Addon Manager manually.