"pop" sound when stop playing SACD on Tx-NR 5010

I am connecting my Sony blu ray player to my onkyo tx-Nr5010 via HDMI. I have my player sending DSD signal to the receiver, and also set the receiver "DSD Direct" to ON. Every time when I stop playing a SACD, the receiver send a loud "pop" sound to the speakers. I am worry that it will damage the speaker. Similar situation also happens when using onkyo app to send mp3 song from cellular phone to receiver except it usually happens before the song start to play. It seems like to me that the "pop" sound happens when DSD signal disconnected from receiver and also happens when signal connect and disconnected when using input "NET (DNLA)".

I remember that I have seen similar situation mentioned on model 5008 or 5009 and has been discussed in AVS forum. Members there mentions that onkyo is able to email a firmware individually to fix the problem.

Please kindly explains what is the exact issue that causing the "pop" sound? Also, does onkyo have any firmware for 5010 model to fix the problem? I am so worry that it will damage the speaker.

thanks