And the clicking is from the speakers, not from the amp?I get clicking with Bluetooth and USB modes, none for the other input types. This is the same on both A30 units.
If so, then I'm guessing you have some source of heavy interference in the system which is corrupting the digital signal.
Do you have the USB connected when using bluetooth? If so, try disconnecting it. Have amp and speakers as the only connected devices and source via bluetooth. If you still get clicking, try moving the exact same devices (amp and speakers) over to the location of your other system and try there.
If that location is OK, try running a mains extension lead over from the location that is OK to the one that isn't, so that the source of power is from the "good" location, but the amp is located at the "bad" location.
Etc
etc