YES..it is a bug because it didn't do this before. I did this many times prior to this update and wasn't hallucinating. When you create a new line, it does not adopt the styles of the previous one. So, if you had a line that had specific styles (weight / different endpoints / shadow / color) on that connector line in which you'd like to use on another slide, it used to be that you could copy the connected line and paste onto a new page (now unconnected of course) and then simply drag/connect them to whatever objects you wanted to. It was very convenient over creating a new line and then reconfiguring all the styles.
Now, you must copy both the connector line and it's connected elements. Then disconnect and delete the unwanted objects and then reconnect the line to the new elements.
So yeah, I see it as a bug. The other option is to create a line style but I would still rather copy/paste.