UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36

Steps to reproduce the problem:
1. add a 'debugger;' statement to code
2. open dev tools
3. run code

What is the expected behavior?
I expect the debugger to break on the 'debugger;'

What went wrong?
It doesn't break...it seems to kind of stutter (a visual flash or something), but doesn't stop.

Did this work before? Yes don't know

Chrome version: 59.0.3071.115  Channel: stable
OS Version: 10.0
Flash Version: 

Other people on the polymer slack channel have seen this too, and one told me that a workaround is to add two 'debugger;' statements in succession, and that does indeed work - ie:

debugger;
debugger;