Lights flash ON, but not OFF during arming

[PajamaGuy]

Sometimes (and I think it's getting more frequent) - when I arm my DS7000, the security lights come ON, but not off.  At other times they act as they're supposed to - On, pause, Off.

[HA Dave]

......... when I arm my DS7000, the security lights come ON, but not off....

Could you be arming the DS7000 as you leave the home... and then also activating or turning OFF other (maybe too many) X10 devices as you exit. I did something similar once disarming.. a combination with a macro that ran when I entered, as well as disarming and activating other devices.... flooded my powerline with X10 signals. A small change in my setup seems to have resolved my problem.