Targets don't detect arrows fired inside of them

The bug

When you set up a dispenser right next to a target, the dispenser fires the arrow inside of the target, and the target doesn't output a signal or detect the arrow.

How to reproduce

1. Place a dispenser right next to a target facing towards it

2. Hook up a redstone output to the target

3. Fill the dispenser with arrows and fire

4. Notice how the target didn't output a signal