Pioneer DDJ-SR2 - Pre-cueing does not work with DJay Pro!

Hey team, so I bought the Pioneer DDJ-SR2 as it is natively supported by Algoriddim now as well as the great Spotify integration for DJay Pro 2.
But why can’t I pre-listen / pre-cueing the next track on deck 2 while deck 1 is active or vice versa?
I can only listen via headphones if the the volume is up.

Something is seriously buggered.
Please advise urgently.