Yes I see that too. It might be what they call a "T-Trade", where the trade actually happened during the day, and for some reason they don't report it until after hours. Any trades that happen during the day must be reported that day, but for some reason they get away with reporting large trades sometimes until after hours on the same day, rather than reporting it in real time. It might be MM's shuffling shares around between them or tying up loose ends or something. Seems like a shady practice. Maybe it happened early in the day, but they delayed reporting it to help keep the price down lower so someone can accumulate more at lower prices or something.
I think they should make these T-trades illegal. If there's a trade, everyone should know about it in real time. The whole T-trade thing is really shady, and if you read about it, the rules for them are very unclear. Probably the unclear rules are why people are allowed to get away with it.
News 
Market Data 
Discover 
