Every weapon that starts with one of these letters A B C D E F G H I J or M, all have incorrect riven stats.
And it's not a "riven disposition" thing where the stats are all off by the same percentage. If you notice in my Magnus screenshot, the -Impact is *almost* correct. But the values on the buffs are way off.
Also, whenever the phone app has the wrong numbers, it's always that the numbers are too low. They're never too high.
I reported this about a year ago as well. I hope with the additional information i just gave you, you can finally fix this.