246 - Editor - Lots of crashes using Line Tool

I'm sure this has been raised as it is pretty annoying,
Since the update I am getting a lot of crashes when trying to use the line tool to connect certain vertices.
So here im just trying to draw a line down an existing edge, holding shift to get the vertex the same lever as the one near the cursor, soon as I let go to draw the line it will crash

I can save at this point, reload and try it it will crash
I can go do other work, drop props, draw lines elsewhere etc, come back to this one and it crashes.
Not the only point I have had the crash, there has been others but I have highlighted this one.

Notes
The original edge was in my map before the update.
I can delete the edge/vertex I am getting the error from and redraw it and it wont crash.
I have yet to get a crash using the line tool from or on new faces/edges (Done on/after 246) but I will update if I do.