I stumbled upon very annoying issue - stock SMS/MMS app doesn't have any notification sound preference in settings and probably supposed to obey default notification sound... but it does not and always plays
Pixie Dust. Additionally, SMS/MMS lists SIM 2 before SIM 1 in the settings, possible caused by swapping SIM-cards in the slots. Is it possible what notification sound became stuck in the telephony provider storage? Can clear it without doing factory reset?
The device is dual SIM Spreadtrum phablet.
Apparently, tag supposed to indicate Android version 6.0 no longer work...