gulp-istanbul: Incorrect Coverage in Node 6

When running in Node 6.3.1 the coverage report is incorrect and shows no test coverage. I’ve included the summary reports from identical code run in both environments.

Node 6

=============================== Coverage summary ===============================
Statements   : 6.27% ( 24/383 )
Branches     : 0% ( 0/97 )
Functions    : 0% ( 0/111 )
Lines        : 7.06% ( 24/340 )
================================================================================

Node 4

=============================== Coverage summary ===============================
Statements   : 40.47% ( 155/383 )
Branches     : 8.25% ( 8/97 )
Functions    : 8.11% ( 9/111 )
Lines        : 38.82% ( 132/340 )
================================================================================