I've seen this before but the edges join together cleanly: one of the edges "merges" (like a freeway on-ramp) with the other edge.

In the demo on the front page, there's clearly a pseudo-node that the edges stop at, and it's jarring.

edit: this thing: http://snap.philsnow.io/2016-11-18T11-19-57.mpfpkk55hj0dunqf...

Indeed, it does look a bit weird in that case. On the other hand check out this flowchart https://code2flow.com/KdNVeJ - the same thing looks very clear here.