Turning on UPS static or somewhat arcing sound

[BillP]

at cold start (i usually turn off my ups)

i turn it on the yellow is blinking, i hear a static or arcing sound if im near or keep my ear beside the ups after the light is stable the sound is gone

the ups is working fine i unplug it respond quickly even i remove the plug

is this normal? i recently search about it and they say its normal......just want to comfim

using APC BX625 floor type