There are great b3 emulations out there. I have V3, B4II, B5, , and a few other plugins. Among them all, the B3x IK Multimedia B3x really stands out. It is also available for IOS.
Were you referring to a hardware instrument or a software GM instrument? the two notes Ab6 and A6 in particular seem to be sustained longer than other notes in that range. Then again, notes in that high range do not have felts in an acoustic piano as if the sustain pedal is pressed down. Also, I checked two other piano plugins including the Kontakt Grandeur and they all sustain but because the notes are high in pitch, they decay fast, too.
