Is this an offset bug in 2015/2016?  If so, was it addressed in 2017?

In SW15 and SW16 this bug(?) occurs when you add a relation to one endpoint of an offset without adjusting the other end in any way, locking the other end.  You can test this simply by drawing a line and offsetting it.  Movement of one of these two endpoints will cause the other to move with the endpoint of the original line (when neither are fixed).  It will act like there is a relation between the endpoints when there isn't and this isn't something that I have found you are able to disable. In the below example, moving the top endpoint first prevented the bottom endpoint from moving but moving the bottom endpoint first allowed the top endpoint to move.  Image album below to illustrate point.  I can see no way that this is beneficial, is there something I'm missing and maybe this is intentional?  Thanks guys

SW 2015/2016 offset bug? - Album on Imgur