Mentions are not replaced properly if there's more than one occurance of it in a tweet

eg:

@NASA_Hubble - NASA's Twitter Account Receives Shorty Award - http://1.usa.gov/HdoCLN (via @NASA) Congratulations, @NASA!!

gets converted to:

@NASA_Hubble - NASA's Twitter Account Recieves Shorty Award - <a href="http://t.co/EROCRxoH">http://1.usa.gov/HdoCLN</a>(via @<a href='gwibber:/user?acct=&name=@<a href='gwibber:/user?acct=&name=@NASA'>NASA</a>'>NASA</a>) Congratulations @NASA!!

rather than:

@NASA_Hubble - NASA's Twitter Account Recieves Shorty Award - <a href="http://t.co/EROCRxoH">http://1.usa.gov/HdoCLN</a>(via @<a href='gwibber:/user?acct=&name=@NASA'>NASA</a>) Congratulations <a href='gwibber:/user?acct=&name=@NASA'>NASA</a>!!

So the first mention gets linkified twice and incorrectly and the subsequent ones not at all.