?- displayed, but no log files contain that value

We’ve been noticing that Piwik is reporting things that look like this:

/sipsig?-

But there is no record of that request in the log files. These are the records that appear in the log files:
2014-01-02 19:31:55 GET /sipsig/aera2000franklin.pdf - - 66.249.73.105 HTTP/1.1 Googlebot/2.1+(+http://www.google.com/bot.html) - 301 413
2014-01-03 01:06:03 GET /sipsig/ - - 180.76.5.190 HTTP/1.1 Mozilla/5.0+(compatible;+Baiduspider/2.0;++http://www.baidu.com/search/spider.html) - 301 392

So why are the pages getting marked with ?- ?

Hi there, this bug should be fixed in the latest beta: http://builds.piwik.org/
if you stil have issue for data imported After having upgraded to latest beta, please create an issue

Will I have to delete my archives for this site or will just upgrading the software update the statistics?

Thanks
Josh

It will only work for the future data, it will not fix the past data.