This isn’t a bug. Its the way the ATR hydraulic systems work.
The hydraulic pumps are powered by the AC Wild generators. The ACW Generator on engine number 2 is powering both hydraulic pumps. If you look on the screen print you provided this is shown by the thinner green line connecting the two engines.
Thin green lines are signifying electrically powered and the thick lines are hydraulic pressure.
The hydraulic cross feed valve is used if there is a hydraulic pump failure and does function correctly.