As far as I understand, at least per Lessig's team:

Dems said in order to participate in debate, you must poll 1% in three polls IN the six weeks prior to the debate. Depending on what polls were counted, Lessig either qualified or were one poll away from doing so.

Dems then “clarified” rules as being 1% in three polls AT LEAST six weeks prior to the debate.

HuffPo op-ed from Lessig's campaign manager: http://www.huffingtonpost.com/steve-jarding/the-democrats-ha...