karma-chrome-launcher: karma crashes when chrome is already running

When launching the karma test with chrome already running, three karma tabs open, connect, lose the connection again and then karma crashes. When you close two of the tabs fast enough, everything works.

INFO [karma]: Karma v0.12.31 server started at http://localhost:9876/
INFO [launcher]: Starting browser Chrome
DEBUG [temp-dir]: Creating temp dir at C:\Users\[...]\AppData\Local\Temp\karma-40710999
DEBUG [launcher]: C:\Program Files (x86)\Google\Chrome\Application\chrome.exe --user-data-dir=C:\Users\[...]\AppData\Local\Temp\karma-40710999 --no-default-browser-check --no-first-run --disable-default-apps --disable-popup-blocking --disable-translate ht
tp://localhost:9876/?id=40710999
DEBUG [framework.browserify]: building bundle
DEBUG [framework.browserify]: adding [...] to bundle
DEBUG [launcher]: Process Chrome exited with code 0
ERROR [launcher]: Cannot start Chrome

DEBUG [temp-dir]: Cleaning temp dir C:\Users\[...]\AppData\Local\Temp\karma-40710999
INFO [launcher]: Trying to start Chrome again (1/2).
DEBUG [launcher]: Restarting Chrome
DEBUG [temp-dir]: Creating temp dir at C:\Users\[...]\AppData\Local\Temp\karma-40710999
DEBUG [launcher]: C:\Program Files (x86)\Google\Chrome\Application\chrome.exe --user-data-dir=C:\Users\[...]\AppData\Local\Temp\karma-40710999 --no-default-browser-check --no-first-run --disable-default-apps --disable-popup-blocking --disable-translate ht
tp://localhost:9876/?id=40710999
DEBUG [launcher]: Process Chrome exited with code 0
ERROR [launcher]: Cannot start Chrome

DEBUG [temp-dir]: Cleaning temp dir C:\Users\[...]\AppData\Local\Temp\karma-40710999
INFO [launcher]: Trying to start Chrome again (2/2).
DEBUG [launcher]: Restarting Chrome
DEBUG [temp-dir]: Creating temp dir at C:\Users\[...]\AppData\Local\Temp\karma-40710999
DEBUG [launcher]: C:\Program Files (x86)\Google\Chrome\Application\chrome.exe --user-data-dir=C:\Users\[...]\AppData\Local\Temp\karma-40710999 --no-default-browser-check --no-first-run --disable-default-apps --disable-popup-blocking --disable-translate ht
tp://localhost:9876/?id=40710999
DEBUG [framework.browserify]: bundling
DEBUG [launcher]: Process Chrome exited with code 0
ERROR [launcher]: Cannot start Chrome

DEBUG [temp-dir]: Cleaning temp dir C:\Users\[...]\AppData\Local\Temp\karma-40710999
DEBUG [web-server]: serving: D:\[...]\node_modules\karma\static/client.html
DEBUG [web-server]: serving (cached): D:\[...]\node_modules\karma\static/client.html
ERROR [launcher]: Chrome failed 2 times (cannot start). Giving up.
DEBUG [web-server]: serving (cached): D:\[...]\node_modules\karma\static/client.html
DEBUG [web-server]: serving: D:\[...]\node_modules\karma\static/karma.js
DEBUG [web-server]: serving (cached): D:\[...]\node_modules\karma\static/karma.js
DEBUG [web-server]: serving (cached): D:\[...]\node_modules\karma\static/karma.js
[...]
DEBUG [web-server]: upgrade /socket.io/1/websocket/hZrbHj-2BzuPr_YNkUmW
DEBUG [karma]: A browser has connected on socket hZrbHj-2BzuPr_YNkUmW
DEBUG [web-server]: upgrade /socket.io/1/websocket/9Nh06gkCmfm7Ag4dkUmX
DEBUG [karma]: A browser has connected on socket 9Nh06gkCmfm7Ag4dkUmX
DEBUG [web-server]: upgrade /socket.io/1/websocket/JFZ5G4UQX3ciOHOnkUmY
DEBUG [karma]: A browser has connected on socket JFZ5G4UQX3ciOHOnkUmY
INFO [Chrome 39.0.2171 (Windows 8.1)]: Connected on socket hZrbHj-2BzuPr_YNkUmW with id 40710999
DEBUG [launcher]: Chrome (id 40710999) captured in 4.242 secs
DEBUG [Chrome 39.0.2171 (Windows 8.1)]: New connection 9Nh06gkCmfm7Ag4dkUmX (already have hZrbHj-2BzuPr_YNkUmW)
DEBUG [Chrome 39.0.2171 (Windows 8.1)]: New connection JFZ5G4UQX3ciOHOnkUmY (already have hZrbHj-2BzuPr_YNkUmW, 9Nh06gkCmfm7Ag4dkUmX)
DEBUG [watcher]: Add file "D:/fab3d-lowfab/testClient/stlImportTest.coffee" ignored. Already in the list.
WARN [Chrome 39.0.2171 (Windows 8.1)]: Disconnected (1 times), because no message in 10000 ms.
ERROR [karma]: [TypeError: Cannot call method 'map' of undefined]
TypeError: Cannot call method 'map' of undefined
  at [object Object]._render (D:\[...]\node_modules\karma\lib\reporters\progress.js:56:27)
  at [object Object]._refresh (D:\[...]\node_modules\karma\lib\reporters\progress.js:60:34)
  at [object Object].onBrowserComplete (D:\[...]\node_modules\karma\lib\reporters\progress.js:19:21)
  at [object Object].<anonymous> (D:\[...]\node_modules\karma\lib\events.js:15:22)
  at [object Object].emit (events.js:117:20)
  at [object Object]._onTimeout (D:\[...]\node_modules\karma\lib\browser.js:53:15)
  at Timer.listOnTimeout [as ontimeout] (timers.js:112:15)

DEBUG [launcher]: Disconnecting all browsers
DEBUG [framework.browserify]: cleaning up