Google has confirmed in a Google AdSense Help thread that many publishers did not received their January payments due to a bug in the system. The bug put publisher accounts on hold, which automatically held any payments being sent to these publishers. Google’s AdSense Pro William confirmed the issue last night, saying:

I believe this is a continuation of the story we covered a couple weeks ago named Google Confirms Not Paying Some AdSense Publishers. Let’s add this to the list of recent bugs we have been noticing with Google in the past week, I think we are over 10 now.

Forum discussion at Google AdSense Help.