Seems like alot of people don't get how that works, let me explain.
Say the spread is 100z200, someone buys at the ask and the PPS is now 200. After a few minutes the ask gets lowered to 100x150 and someone BUYS at the ask again, the PPS is now 150 and every L2 software is going to show this as red which DOESN'T mean a sale, it means a downtick.
It goes the other way too. If the spread is 100x200 and someone sells at the bid, the PPS is 100. If the bid is then raised to 150x200 and someone SELLS at the bid again, the PPS goes up to 150 and in every L2 software it will show as green which DOESN'T mean a buy, it means an uptick.
In conclusion green/red does not equal buy/sell, it means uptick/downtick.
We are seeing alot of that going on because the ask and bid are constantly manipulated to cause red and green (mostly red)