Create a symmetrical angular dimension

I found a strange behaviour when I used a symmetrical angular dimension.

1. I selected the centerline and a non-parallel line. So far so good.

2. I pressed and held the shift key to switch to symmetrical angular dimension, and the result was odd.

Have you seen that and is that a bug.

I use SW2016 SP3.

Thanks

Tateos

SolidworksParts And Features