I don't think so. I've seen that with a lot of stocks where VERT is on the BID/ASK. At the end of the day there is 1 large sell which is equal to the number of shares VERT sold the rest of the day.
Today 1,667,500 shares were either bought from VERT or VERT sold them on the BID. Then at 15:59 1 large trade for 1,677,500 shares executed.
I'm not sure if it is an accounting thing or why that happens.