Hi!
It doesn't sound like anything bad. I've seen players do weird things after brief hydro interruptions, or after having their plugs hit slightly, momentarily disconnecting them.
Even when a player is in stand-by, it's still "on" and powered-up; only the display is off. A brief power outage or surge could cause the laser to try and read a disc that is not in the player, so it goes into a fit bouncing up and down until you turn it off. If it's a top-loading CD player or if the cover is off you can actually see it happening.
It sounds like you have a good dealer, and you have told him about it, so you should be okay.
It doesn't sound like anything bad. I've seen players do weird things after brief hydro interruptions, or after having their plugs hit slightly, momentarily disconnecting them.
Even when a player is in stand-by, it's still "on" and powered-up; only the display is off. A brief power outage or surge could cause the laser to try and read a disc that is not in the player, so it goes into a fit bouncing up and down until you turn it off. If it's a top-loading CD player or if the cover is off you can actually see it happening.
It sounds like you have a good dealer, and you have told him about it, so you should be okay.