Hi,i have had this issue before,never posted about it.
i have a template in cubase 11 pro,with battery 4 on it.
i have a kit loaded and a kick on a midi track.when i press key on midi keyboard i can hear the kick.
if i add another midi track the only sound i can preview(hear) is the kick.
i can see the other pads flashing when i press corresponding keys on midi keyboard,i just cant hear them.

now,if i open a new project and load battery 4 it works fine.
all sounds can be heard when i play midi keyboard.
when i create new midi tracks i can play the other sounds no prob.
why oh why does this happen?