Is it possible that SI just wants to take advantage of other deals in the market? Remember he's selling a stock that is in the green. He could be buying other stocks and using free money to pay for them. If this was the case we don't have to consider that POET R&D is having problems other than missing the mark on the timelines.
Nevertheless, POET should have released an update. In that case the market would have been reassured prior to SI's activities. I don't criticize POET often, but this was a blunder to say the least.