TypeError: Cannot read property 'start' of undefined

Trying to figure out what this is all about. Not sure what exactly is being pushed into object-utils.
Any ideas? FWIW I'm using this instrumenter https://github.com/deepsweet/istanbul-instrumenter-loader

```
15 12 2015 16:47:52.674:ERROR [coverage]: [TypeError: Cannot read property 'start' of undefined]
TypeError: Cannot read property 'start' of undefined
at /home/adjavaherian/Desktop/web-off-master/node_modules/istanbul/lib/object-utils.js:59:44
at Array.forEach (native)
at Object.addDerivedInfoForFile (/home/adjavaherian/Desktop/web-off-master/node_modules/istanbul/lib/object-utils.js:58:37)
at Object.Collector.fileCoverageFor (/home/adjavaherian/Desktop/web-off-master/node_modules/istanbul/lib/collector.js:94:15)
at /home/adjavaherian/Desktop/web-off-master/node_modules/istanbul/lib/report/text.js:210:27
at Array.forEach (native)
at TextReport.Report.mix.writeReport (/home/adjavaherian/Desktop/web-off-master/node_modules/istanbul/lib/report/text.js:208:27)
at writeReport (/home/adjavaherian/Desktop/web-off-master/node_modules/karma-coverage/lib/reporter.js:62:16)
at /home/adjavaherian/Desktop/web-off-master/node_modules/karma-coverage/lib/reporter.js:282:11
at Array.forEach (native)
at forEach (/home/adjavaherian/Desktop/web-off-master/node_modules/karma/lib/browser_collection.js:93:21)
at /home/adjavaherian/Desktop/web-off-master/node_modules/karma-coverage/lib/reporter.js:241:16
at Array.forEach (native)
at onRunComplete (/home/adjavaherian/Desktop/web-off-master/node_modules/karma-coverage/lib/reporter.js:240:15)
at null. (/home/adjavaherian/Desktop/web-off-master/node_modules/karma/lib/events.js:13:22)
at emitTwo (events.js:92:20)
```