I guess there were some line (or polygon edge?) changes with the new style. It turns out this broke Barbs. Here are the results running the barb_demo.py example.

Good (1.5.x):

Bad (master):

It turns out that there are 0 tests for the Barbs code. I'm willing to submit a PR to fix the problem and add some tests (probably just knock off the demo). Since I think I've seen mention of similar issues elsewhere, can someone point me to what exactly needs to be added, maybe some kind of edge/line style or color?