To even be able to use the mouse to move any kind of levers on a multi-engine setup you need to be able to move more than one lever at a time.
I use the keyboard or my Hotas One joystick/thrust lever to make power adjustments.
Yes, there are lots of ways to move the levers, but this is not helping the fact that using the mouse on multi-engine setup does not work.
Not a bug.
Perhaps, a wishlist item at best, but certainly not a bug.
Maybe there’s a way to map all axis to the scroll wheel or a mouse button ?
Makes it even more interesting when being in need of re-syncing the propellers after manipulating individual fuel leaning and prop RPM settings 
Since this is the “Bugs & Issues” forum I’d say it’s an issue. And for me a serious issue. Mostly because I play in VR. I could post this in the VR section, but lets start at the beginning where this should be normal mouse behaviour for anyone.
Left clicking to select a single lever and right clicking to select all levers of same type seems pretty easy to me.