Aesthetix Atlas question


I have the Atlas monoblocks, which I keep in Standby when not in use. When the units come out of Standby, the bass drivers of both speakers briefly (maybe 1 second) go to full or near-full excursion. I've had this happen with two different pair of speakers, both medium efficiency. Has anyone else had this experience, and should I be worried?
psag
Just happened last night. The preamp was muted and On for about 15 minutes before I started turning ON the Atlas. After about 10 minutes later, the left speaker suddenly produced an explosion sound. I rushed to turn off the Atlas. No smell. After waiting for another 30 minutes, I turned on the Atlas and this time, after it turned blue, I quickly muted the amp. There was a pop sound. I waited for about another 10 minutes and unmuted. Well, nothing..I could play that amp. Thank goodness!