ArgumentOutOfRangeException randomly thrown when generating "rand" tracking parameter

[ErlendSB]

Any idea why this is happening?

System.ArgumentOutOfRangeException: Index and length must refer to a location within the string.
Parameter name: length
at System.String.InternalSubStringWithChecks(Int32 startIndex, Int32 length, Boolean fAlwaysCopy)
at System.String.Substring(Int32 startIndex, Int32 length)
at Piwik.Tracker.PiwikTracker.getRequest(Int32 idSite)
at Piwik.Tracker.PiwikTracker.getUrlTrackPageView(String documentTitle)
at Piwik.Tracker.PiwikTracker.doTrackPageView(String documentTitle)

I believe it is at Line 817:
Convert.ToString(new Random().Next()).Substring(2, 6)

[julienmoumne]

It's indeed a bug: new Random().Next() does not necessary produce a 6 digits number.