Cannot send GA Custom Event if querystring has an underscore

[GoogleCodeExporter]

---------------------------------------------------------------------------
NOTE: This issue tracking system is for Google Analytics developer products
only.
If you are not a developer/programmer visit:
http://www.google.com/analytics/support.html
---------------------------------------------------------------------------
Name of affected component: Web Tracking (analytics.js)

Issue summary:
I recognized that if an underscore is provided in a querystring its impossible 
to send custom events via ga('send',[...]) to Google Analytics. But in general 
underscores are valid in querystrings, isnt it?

Steps to reproduce issue:
1. enter website like example.com/page/1?foo_bar=baz
2. trigger 
ga('send',{"hitType":"event","eventCategory":"FOO","eventAction":"BAR","eventLab
el":"BAZ"}); on developer console
3. look into real time events in Google Analytics

Expected output:
I expect to see my sent events in the real time monitoring.

Actual results:
I dont see my sent events in the real time monitoring.

Looking forward to hear from you.

King regards
Maik

Original issue reported on code.google.com by m...@happycar.de on 30 Jun 2015 at 3:33